Effects of Threshold Adjustment on Speech Perception in Nucleus Cochlear Implant Recipients.

Objective: The objective of this study was to investigate the impact of using smaller and larger electric dynamic ranges on speech perception, aided thresholds, and subjective preference in cochlear implant (CI) subjects with the Nucleus(R) device. Design: Data were collected from 19 adults using the Nucleus CI system. Current levels (CLs) used to set threshold stimulation levels (T-levels) were set above or below the measured hearing thresholds to create smaller or larger electric output dynamic ranges, respectively, whereas the upper stimulation level (C-level) was fixed. The base (unadjusted) condition was compared against two conditions with higher T-levels (compression), by 30% and 60% of the measured hearing dynamic range, and three conditions with lower T-levels (expansion), by 30%, 60%, and 90% of the measured hearing dynamic range. For each subject, the clinical CL units were adjusted on each electrode to achieve these conditions. The slow-acting dynamic acoustic gains of ADRO(R) and Autosensitivity(TM) were enabled. Consonant-nucleus-consonant (CNC) word scores were measured in quiet at 50 dB and 60 dB SPL presentation levels. The signal-to-noise ratios (SNRs) for 50% understanding of sentences in noise were measured for sentences presented at 55 dB and 65 dB SPL in 4-talker babble noise. Free-field aided thresholds were measured at octave frequencies using frequency-modulated (warble) tones. Thirteen of the 19 subjects had take-home experience with the base and experimental conditions and provided subjective feedback via a questionnaire. Results: There were no significant effects of 30% expansion and 30% compression of the electric dynamic range on scores for words in quiet and SNRs for sentences in noise, at the two presentation levels. There was a significant decrement in scores for words in quiet for 60% and 90% expansion compared with the base condition at the 50 dB and 60 dB SPL presentation levels. The score decrement was much less at 60 dB SPL. For the 50 dB SPL presentation level, the decrements in word scores at 60% and 90% expansion were linearly related to the reduction in CL units required to achieve these experimental conditions, with a greater decrement in scores for a larger CL change. There was a significant increase in SNR for sentences in noise for 60% compression compared with the base condition at the 55 dB and 65 dB SPL presentation levels. There was also a significant increase in SNR for sentences at the 55 dB SPL presentation level for 90% expansion. Aided thresholds were significantly elevated for the three expansion conditions compared with the base condition, although the mean elevation at 30% expansion was only 4 dB. The questionnaire results showed no clear preference for any condition; however, subjects reported a reduced preference for the extreme compression (60%) and expansion (90%) conditions. Conclusions: The results showed that CI subjects using the Nucleus sound processor had no significant change in performance or preference for adjustments in T-levels by +/-30% of the hearing dynamic range. In quiet, speech perception scores were reduced for the more marked expansion (60% and 90%) conditions, whereas in noise, performance was poorer for the highest compression (60%) condition. Across subjects, the decrement in scores for words at 50 dB SPL for the 60% and 90% expansion conditions was related to the changes in CL units required for these conditions, with greater decrements for larger changes in levels. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1RHvCG6
via IFTTT

The Use of the Kurtosis-Adjusted Cumulative Noise Exposure Metric in Evaluating the Hearing Loss Risk for Complex Noise.

Objective: To test a kurtosis-adjusted cumulative noise exposure (CNE) metric for use in evaluating the risk of hearing loss among workers exposed to industrial noises. Specifically, to evaluate whether the kurtosis-adjusted CNE (1) provides a better association with observed industrial noise-induced hearing loss, and (2) provides a single metric applicable to both complex (non-Gaussian [non-G]) and continuous or steady state (Gaussian [G]) noise exposures for predicting noise-induced hearing loss (dose-response curves). Design: Audiometric and noise exposure data were acquired on a population of screened workers (N = 341) from two steel manufacturing plants located in Zhejiang province and a textile manufacturing plant located in Henan province, China. All the subjects from the two steel manufacturing plants (N = 178) were exposed to complex noise, whereas the subjects from textile manufacturing plant (N = 163) were exposed to a G continuous noise. Each subject was given an otologic examination to determine their pure-tone HTL and had their personal 8-hr equivalent A-weighted noise exposure (LAeq) and full-shift noise kurtosis statistic (which is sensitive to the peaks and temporal characteristics of noise exposures) measured. For each subject, an unadjusted and kurtosis-adjusted CNE index for the years worked was created. Multiple linear regression analysis controlling for age was used to determine the relationship between CNE (unadjusted and kurtosis adjusted) and the mean HTL at 3, 4, and 6 kHz (HTL346) among the complex noise-exposed group. In addition, each subject's HTLs from 0.5 to 8.0 kHz were age and sex adjusted using Annex A (ISO-1999) to determine whether they had adjusted high-frequency noise-induced hearing loss (AHFNIHL), defined as an adjusted HTL shift of 30 dB or greater at 3.0, 4.0, or 6.0 kHz in either ear. Dose-response curves for AHFNIHL were developed separately for workers exposed to G and non-G noise using both unadjusted and adjusted CNE as the exposure matric. Results: Multiple linear regression analysis among complex exposed workers demonstrated that the correlation between HTL3,4,6 and CNE controlling for age was improved when using the kurtosis-adjusted CNE compared with the unadjusted CNE (R2 = 0.386 versus 0.350) and that noise accounted for a greater proportion of hearing loss. In addition, although dose-response curves for AHFNIHL were distinctly different when using unadjusted CNE, they overlapped when using the kurtosis-adjusted CNE. Conclusions: For the same exposure level, the prevalence of NIHL is greater in workers exposed to complex noise environments than in workers exposed to a continuous noise. Kurtosis adjustment of CNE improved the correlation with NIHL and provided a single metric for dose-response effects across different types of noise. The kurtosis-adjusted CNE may be a reasonable candidate for use in NIHL risk assessment across a wide variety of noise environments. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1RHvB4S
via IFTTT

Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness.

Objectives: This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Design: Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening. Results: Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a similar level of monaural performance (50%), binaural integration advantages were found regardless of whether a mismatch was simulated or not. When the CI-simulation ear supported a superior level of monaural performance (71%), evidence of binaural integration was absent when a mismatch was simulated using both the Realistic and the Ideal processing strategies. This absence of integration could not be accounted for by ceiling effects or by changes in SNR. Conclusions: If generalizable to unilaterally deaf CI users, the results of the current simulation study would suggest that benefits to speech perception in noise can be obtained by integrating information from an implanted ear and an NH ear. A mismatch in the delivery of spectral information between the ears due to a misalignment in the mapping of frequency to place may disrupt binaural integration in situations where both ears cannot support a similar level of monaural speech understanding. Previous studies that have measured the speech perception of unilaterally deaf individuals after CI but with nonindividualized frequency-to-electrode allocations may therefore have underestimated the potential benefits of providing binaural hearing. However, it remains unclear whether the size and nature of the potential incremental benefits from individualized allocations are sufficient to justify the time and resources required to derive them based on cochlear imaging or pitch-matching tasks. This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1Nf3o2a
via IFTTT

Temporal Response Properties of the Auditory Nerve in Implanted Children with Auditory Neuropathy Spectrum Disorder and Implanted Children with Sensorineural Hearing Loss.

Objective: This study aimed to (1) characterize temporal response properties of the auditory nerve in implanted children with auditory neuropathy spectrum disorder (ANSD), and (2) compare results recorded in implanted children with ANSD with those measured in implanted children with sensorineural hearing loss (SNHL). Design: Participants included 28 children with ANSD and 29 children with SNHL. All subjects used cochlear nucleus devices in their test ears. Both ears were tested in 6 children with ANSD and 3 children with SNHL. For all other subjects, only one ear was tested. The electrically evoked compound action potential (ECAP) was measured in response to each of the 33 pulses in a pulse train (excluding the second pulse) for one apical, one middle-array, and one basal electrode. The pulse train was presented in a monopolar-coupled stimulation mode at 4 pulse rates: 500, 900, 1800, and 2400 pulses per second. Response metrics included the averaged amplitude, latencies of response components and response width, the alternating depth and the amount of neural adaptation. These dependent variables were quantified based on the last six ECAPs or the six ECAPs occurring within a time window centered around 11 to 12 msec. A generalized linear mixed model was used to compare these dependent variables between the 2 subject groups. The slope of the linear fit of the normalized ECAP amplitudes (re. amplitude of the first ECAP response) over the duration of the pulse train was used to quantify the amount of ECAP increment over time for a subgroup of 9 subjects. Results: Pulse train-evoked ECAPs were measured in all but 8 subjects (5 with ANSD and 3 with SNHL). ECAPs measured in children with ANSD had smaller amplitude, longer averaged P2 latency and greater response width than children with SNHL. However, differences in these two groups were only observed for some electrodes. No differences in averaged N1 latency or in the alternating depth were observed between children with ANSD and children with SNHL. Neural adaptation measured in these 2 subject groups was comparable for relatively short durations of stimulation (i.e., 11 to 12 msec). Children with ANSD showed greater neural adaptation than children with SNHL for a longer duration of stimulation. Amplitudes of ECAP responses rapidly declined within the first few milliseconds of stimulation, followed by a gradual decline up to 64 msec after stimulus onset in the majority of subjects. This decline exhibited an alternating pattern at some pulse rates. Further increases in pulse rate diminished this alternating pattern. In contrast, ECAPs recorded from at least one stimulating electrode in six ears with ANSD and three ears with SNHL showed a clear increase in amplitude over the time course of stimulation. The slope of linear regression functions measured in these subjects was significantly greater than zero. Conclusions: Some but not all aspects of temporal response properties of the auditory nerve measured in this study differ between implanted children with ANSD and implanted children with SNHL. These differences are observed for some but not all electrodes. A new neural response pattern is identified. Further studies investigating its underlying mechanism and clinical relevance are warranted. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1Nf3nLS
via IFTTT

Acoustic Cue Weighting by Adults with Cochlear Implants: A Mismatch Negativity Study.

Objectives: Formant rise time (FRT) and amplitude rise time (ART) are acoustic cues that inform phonetic identity. FRT represents the rate of transition of the formant(s) to a steady state, while ART represents the rate at which the sound reaches its peak amplitude. Normal-hearing (NH) native English speakers weight FRT more than ART during the perceptual labeling of the /ba/-/wa/ contrast. This weighting strategy is reflected neurophysiologically in the magnitude of the mismatch negativity (MMN)-MMN is larger during the FRT than the ART distinction. The present study examined the neurophysiological basis of acoustic cue weighting in adult cochlear implant (CI) listeners using the MMN design. It was hypothesized that individuals with CIs who weight ART more in behavioral labeling (ART users) would show larger MMNs during the ART than the FRT contrast, and the opposite would be seen for FRT users. Design: Electroencephalography was recorded while 20 adults with CIs listened passively to combinations of 3 synthetic speech stimuli: a /ba/ with /ba/-like FRT and ART; a /wa/ with /wa/-like FRT and ART; and a /ba/wa stimulus with /ba/-like FRT and /wa/-like ART. The MMN response was elicited during the FRT contrast by having participants passively listen to a train of /wa/ stimuli interrupted occasionally by /ba/wa stimuli, and vice versa. For the ART contrast, the same procedure was implemented using the /ba/ and /ba/wa stimuli. Results: Both ART and FRT users with CIs elicited MMNs that were equal in magnitudes during FRT and ART contrasts, with the exception that FRT users exhibited MMNs for ART and FRT contrasts that were temporally segregated. That is, their MMNs occurred significantly earlier during the ART contrast (~100 msec following sound onset) than during the FRT contrast (~200 msec). In contrast, the MMNs for ART users of both contrasts occurred later and were not significantly separable in time (~230 msec). Interestingly, this temporal segregation observed in FRT users is consistent with the MMN behavior in NH listeners. Conclusions: Results suggest that listeners with CIs who learn to classify phonemes based on formant dynamics, consistent with NH listeners, develop a strategy similar to NH listeners, in which the organization of the amplitude and spectral representations of phonemes in auditory memory are temporally segregated. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1Nf3o2l
via IFTTT

Effects of Threshold Adjustment on Speech Perception in Nucleus Cochlear Implant Recipients.

Objective: The objective of this study was to investigate the impact of using smaller and larger electric dynamic ranges on speech perception, aided thresholds, and subjective preference in cochlear implant (CI) subjects with the Nucleus(R) device. Design: Data were collected from 19 adults using the Nucleus CI system. Current levels (CLs) used to set threshold stimulation levels (T-levels) were set above or below the measured hearing thresholds to create smaller or larger electric output dynamic ranges, respectively, whereas the upper stimulation level (C-level) was fixed. The base (unadjusted) condition was compared against two conditions with higher T-levels (compression), by 30% and 60% of the measured hearing dynamic range, and three conditions with lower T-levels (expansion), by 30%, 60%, and 90% of the measured hearing dynamic range. For each subject, the clinical CL units were adjusted on each electrode to achieve these conditions. The slow-acting dynamic acoustic gains of ADRO(R) and Autosensitivity(TM) were enabled. Consonant-nucleus-consonant (CNC) word scores were measured in quiet at 50 dB and 60 dB SPL presentation levels. The signal-to-noise ratios (SNRs) for 50% understanding of sentences in noise were measured for sentences presented at 55 dB and 65 dB SPL in 4-talker babble noise. Free-field aided thresholds were measured at octave frequencies using frequency-modulated (warble) tones. Thirteen of the 19 subjects had take-home experience with the base and experimental conditions and provided subjective feedback via a questionnaire. Results: There were no significant effects of 30% expansion and 30% compression of the electric dynamic range on scores for words in quiet and SNRs for sentences in noise, at the two presentation levels. There was a significant decrement in scores for words in quiet for 60% and 90% expansion compared with the base condition at the 50 dB and 60 dB SPL presentation levels. The score decrement was much less at 60 dB SPL. For the 50 dB SPL presentation level, the decrements in word scores at 60% and 90% expansion were linearly related to the reduction in CL units required to achieve these experimental conditions, with a greater decrement in scores for a larger CL change. There was a significant increase in SNR for sentences in noise for 60% compression compared with the base condition at the 55 dB and 65 dB SPL presentation levels. There was also a significant increase in SNR for sentences at the 55 dB SPL presentation level for 90% expansion. Aided thresholds were significantly elevated for the three expansion conditions compared with the base condition, although the mean elevation at 30% expansion was only 4 dB. The questionnaire results showed no clear preference for any condition; however, subjects reported a reduced preference for the extreme compression (60%) and expansion (90%) conditions. Conclusions: The results showed that CI subjects using the Nucleus sound processor had no significant change in performance or preference for adjustments in T-levels by +/-30% of the hearing dynamic range. In quiet, speech perception scores were reduced for the more marked expansion (60% and 90%) conditions, whereas in noise, performance was poorer for the highest compression (60%) condition. Across subjects, the decrement in scores for words at 50 dB SPL for the 60% and 90% expansion conditions was related to the changes in CL units required for these conditions, with greater decrements for larger changes in levels. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1RHvCG6
via IFTTT

The Use of the Kurtosis-Adjusted Cumulative Noise Exposure Metric in Evaluating the Hearing Loss Risk for Complex Noise.

Objective: To test a kurtosis-adjusted cumulative noise exposure (CNE) metric for use in evaluating the risk of hearing loss among workers exposed to industrial noises. Specifically, to evaluate whether the kurtosis-adjusted CNE (1) provides a better association with observed industrial noise-induced hearing loss, and (2) provides a single metric applicable to both complex (non-Gaussian [non-G]) and continuous or steady state (Gaussian [G]) noise exposures for predicting noise-induced hearing loss (dose-response curves). Design: Audiometric and noise exposure data were acquired on a population of screened workers (N = 341) from two steel manufacturing plants located in Zhejiang province and a textile manufacturing plant located in Henan province, China. All the subjects from the two steel manufacturing plants (N = 178) were exposed to complex noise, whereas the subjects from textile manufacturing plant (N = 163) were exposed to a G continuous noise. Each subject was given an otologic examination to determine their pure-tone HTL and had their personal 8-hr equivalent A-weighted noise exposure (LAeq) and full-shift noise kurtosis statistic (which is sensitive to the peaks and temporal characteristics of noise exposures) measured. For each subject, an unadjusted and kurtosis-adjusted CNE index for the years worked was created. Multiple linear regression analysis controlling for age was used to determine the relationship between CNE (unadjusted and kurtosis adjusted) and the mean HTL at 3, 4, and 6 kHz (HTL346) among the complex noise-exposed group. In addition, each subject's HTLs from 0.5 to 8.0 kHz were age and sex adjusted using Annex A (ISO-1999) to determine whether they had adjusted high-frequency noise-induced hearing loss (AHFNIHL), defined as an adjusted HTL shift of 30 dB or greater at 3.0, 4.0, or 6.0 kHz in either ear. Dose-response curves for AHFNIHL were developed separately for workers exposed to G and non-G noise using both unadjusted and adjusted CNE as the exposure matric. Results: Multiple linear regression analysis among complex exposed workers demonstrated that the correlation between HTL3,4,6 and CNE controlling for age was improved when using the kurtosis-adjusted CNE compared with the unadjusted CNE (R2 = 0.386 versus 0.350) and that noise accounted for a greater proportion of hearing loss. In addition, although dose-response curves for AHFNIHL were distinctly different when using unadjusted CNE, they overlapped when using the kurtosis-adjusted CNE. Conclusions: For the same exposure level, the prevalence of NIHL is greater in workers exposed to complex noise environments than in workers exposed to a continuous noise. Kurtosis adjustment of CNE improved the correlation with NIHL and provided a single metric for dose-response effects across different types of noise. The kurtosis-adjusted CNE may be a reasonable candidate for use in NIHL risk assessment across a wide variety of noise environments. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1RHvB4S
via IFTTT

Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness.

Objectives: This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Design: Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening. Results: Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a similar level of monaural performance (50%), binaural integration advantages were found regardless of whether a mismatch was simulated or not. When the CI-simulation ear supported a superior level of monaural performance (71%), evidence of binaural integration was absent when a mismatch was simulated using both the Realistic and the Ideal processing strategies. This absence of integration could not be accounted for by ceiling effects or by changes in SNR. Conclusions: If generalizable to unilaterally deaf CI users, the results of the current simulation study would suggest that benefits to speech perception in noise can be obtained by integrating information from an implanted ear and an NH ear. A mismatch in the delivery of spectral information between the ears due to a misalignment in the mapping of frequency to place may disrupt binaural integration in situations where both ears cannot support a similar level of monaural speech understanding. Previous studies that have measured the speech perception of unilaterally deaf individuals after CI but with nonindividualized frequency-to-electrode allocations may therefore have underestimated the potential benefits of providing binaural hearing. However, it remains unclear whether the size and nature of the potential incremental benefits from individualized allocations are sufficient to justify the time and resources required to derive them based on cochlear imaging or pitch-matching tasks. This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1Nf3o2a
via IFTTT

Temporal Response Properties of the Auditory Nerve in Implanted Children with Auditory Neuropathy Spectrum Disorder and Implanted Children with Sensorineural Hearing Loss.

Objective: This study aimed to (1) characterize temporal response properties of the auditory nerve in implanted children with auditory neuropathy spectrum disorder (ANSD), and (2) compare results recorded in implanted children with ANSD with those measured in implanted children with sensorineural hearing loss (SNHL). Design: Participants included 28 children with ANSD and 29 children with SNHL. All subjects used cochlear nucleus devices in their test ears. Both ears were tested in 6 children with ANSD and 3 children with SNHL. For all other subjects, only one ear was tested. The electrically evoked compound action potential (ECAP) was measured in response to each of the 33 pulses in a pulse train (excluding the second pulse) for one apical, one middle-array, and one basal electrode. The pulse train was presented in a monopolar-coupled stimulation mode at 4 pulse rates: 500, 900, 1800, and 2400 pulses per second. Response metrics included the averaged amplitude, latencies of response components and response width, the alternating depth and the amount of neural adaptation. These dependent variables were quantified based on the last six ECAPs or the six ECAPs occurring within a time window centered around 11 to 12 msec. A generalized linear mixed model was used to compare these dependent variables between the 2 subject groups. The slope of the linear fit of the normalized ECAP amplitudes (re. amplitude of the first ECAP response) over the duration of the pulse train was used to quantify the amount of ECAP increment over time for a subgroup of 9 subjects. Results: Pulse train-evoked ECAPs were measured in all but 8 subjects (5 with ANSD and 3 with SNHL). ECAPs measured in children with ANSD had smaller amplitude, longer averaged P2 latency and greater response width than children with SNHL. However, differences in these two groups were only observed for some electrodes. No differences in averaged N1 latency or in the alternating depth were observed between children with ANSD and children with SNHL. Neural adaptation measured in these 2 subject groups was comparable for relatively short durations of stimulation (i.e., 11 to 12 msec). Children with ANSD showed greater neural adaptation than children with SNHL for a longer duration of stimulation. Amplitudes of ECAP responses rapidly declined within the first few milliseconds of stimulation, followed by a gradual decline up to 64 msec after stimulus onset in the majority of subjects. This decline exhibited an alternating pattern at some pulse rates. Further increases in pulse rate diminished this alternating pattern. In contrast, ECAPs recorded from at least one stimulating electrode in six ears with ANSD and three ears with SNHL showed a clear increase in amplitude over the time course of stimulation. The slope of linear regression functions measured in these subjects was significantly greater than zero. Conclusions: Some but not all aspects of temporal response properties of the auditory nerve measured in this study differ between implanted children with ANSD and implanted children with SNHL. These differences are observed for some but not all electrodes. A new neural response pattern is identified. Further studies investigating its underlying mechanism and clinical relevance are warranted. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via ola Kala on Inoreader http://ift.tt/1Nf3nLS
via IFTTT

Acoustic Cue Weighting by Adults with Cochlear Implants: A Mismatch Negativity Study.

Objectives: Formant rise time (FRT) and amplitude rise time (ART) are acoustic cues that inform phonetic identity. FRT represents the rate of transition of the formant(s) to a steady state, while ART represents the rate at which the sound reaches its peak amplitude. Normal-hearing (NH) native English speakers weight FRT more than ART during the perceptual labeling of the /ba/-/wa/ contrast. This weighting strategy is reflected neurophysiologically in the magnitude of the mismatch negativity (MMN)-MMN is larger during the FRT than the ART distinction. The present study examined the neurophysiological basis of acoustic cue weighting in adult cochlear implant (CI) listeners using the MMN design. It was hypothesized that individuals with CIs who weight ART more in behavioral labeling (ART users) would show larger MMNs during the ART than the FRT contrast, and the opposite would be seen for FRT users. Design: Electroencephalography was recorded while 20 adults with CIs listened passively to combinations of 3 synthetic speech stimuli: a /ba/ with /ba/-like FRT and ART; a /wa/ with /wa/-like FRT and ART; and a /ba/wa stimulus with /ba/-like FRT and /wa/-like ART. The MMN response was elicited during the FRT contrast by having participants passively listen to a train of /wa/ stimuli interrupted occasionally by /ba/wa stimuli, and vice versa. For the ART contrast, the same procedure was implemented using the /ba/ and /ba/wa stimuli. Results: Both ART and FRT users with CIs elicited MMNs that were equal in magnitudes during FRT and ART contrasts, with the exception that FRT users exhibited MMNs for ART and FRT contrasts that were temporally segregated. That is, their MMNs occurred significantly earlier during the ART contrast (~100 msec following sound onset) than during the FRT contrast (~200 msec). In contrast, the MMNs for ART users of both contrasts occurred later and were not significantly separable in time (~230 msec). Interestingly, this temporal segregation observed in FRT users is consistent with the MMN behavior in NH listeners. Conclusions: Results suggest that listeners with CIs who learn to classify phonemes based on formant dynamics, consistent with NH listeners, develop a strategy similar to NH listeners, in which the organization of the amplitude and spectral representations of phonemes in auditory memory are temporally segregated. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Nf3o2l
via IFTTT

Effects of Threshold Adjustment on Speech Perception in Nucleus Cochlear Implant Recipients.

Objective: The objective of this study was to investigate the impact of using smaller and larger electric dynamic ranges on speech perception, aided thresholds, and subjective preference in cochlear implant (CI) subjects with the Nucleus(R) device. Design: Data were collected from 19 adults using the Nucleus CI system. Current levels (CLs) used to set threshold stimulation levels (T-levels) were set above or below the measured hearing thresholds to create smaller or larger electric output dynamic ranges, respectively, whereas the upper stimulation level (C-level) was fixed. The base (unadjusted) condition was compared against two conditions with higher T-levels (compression), by 30% and 60% of the measured hearing dynamic range, and three conditions with lower T-levels (expansion), by 30%, 60%, and 90% of the measured hearing dynamic range. For each subject, the clinical CL units were adjusted on each electrode to achieve these conditions. The slow-acting dynamic acoustic gains of ADRO(R) and Autosensitivity(TM) were enabled. Consonant-nucleus-consonant (CNC) word scores were measured in quiet at 50 dB and 60 dB SPL presentation levels. The signal-to-noise ratios (SNRs) for 50% understanding of sentences in noise were measured for sentences presented at 55 dB and 65 dB SPL in 4-talker babble noise. Free-field aided thresholds were measured at octave frequencies using frequency-modulated (warble) tones. Thirteen of the 19 subjects had take-home experience with the base and experimental conditions and provided subjective feedback via a questionnaire. Results: There were no significant effects of 30% expansion and 30% compression of the electric dynamic range on scores for words in quiet and SNRs for sentences in noise, at the two presentation levels. There was a significant decrement in scores for words in quiet for 60% and 90% expansion compared with the base condition at the 50 dB and 60 dB SPL presentation levels. The score decrement was much less at 60 dB SPL. For the 50 dB SPL presentation level, the decrements in word scores at 60% and 90% expansion were linearly related to the reduction in CL units required to achieve these experimental conditions, with a greater decrement in scores for a larger CL change. There was a significant increase in SNR for sentences in noise for 60% compression compared with the base condition at the 55 dB and 65 dB SPL presentation levels. There was also a significant increase in SNR for sentences at the 55 dB SPL presentation level for 90% expansion. Aided thresholds were significantly elevated for the three expansion conditions compared with the base condition, although the mean elevation at 30% expansion was only 4 dB. The questionnaire results showed no clear preference for any condition; however, subjects reported a reduced preference for the extreme compression (60%) and expansion (90%) conditions. Conclusions: The results showed that CI subjects using the Nucleus sound processor had no significant change in performance or preference for adjustments in T-levels by +/-30% of the hearing dynamic range. In quiet, speech perception scores were reduced for the more marked expansion (60% and 90%) conditions, whereas in noise, performance was poorer for the highest compression (60%) condition. Across subjects, the decrement in scores for words at 50 dB SPL for the 60% and 90% expansion conditions was related to the changes in CL units required for these conditions, with greater decrements for larger changes in levels. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1RHvCG6
via IFTTT

The Use of the Kurtosis-Adjusted Cumulative Noise Exposure Metric in Evaluating the Hearing Loss Risk for Complex Noise.

Objective: To test a kurtosis-adjusted cumulative noise exposure (CNE) metric for use in evaluating the risk of hearing loss among workers exposed to industrial noises. Specifically, to evaluate whether the kurtosis-adjusted CNE (1) provides a better association with observed industrial noise-induced hearing loss, and (2) provides a single metric applicable to both complex (non-Gaussian [non-G]) and continuous or steady state (Gaussian [G]) noise exposures for predicting noise-induced hearing loss (dose-response curves). Design: Audiometric and noise exposure data were acquired on a population of screened workers (N = 341) from two steel manufacturing plants located in Zhejiang province and a textile manufacturing plant located in Henan province, China. All the subjects from the two steel manufacturing plants (N = 178) were exposed to complex noise, whereas the subjects from textile manufacturing plant (N = 163) were exposed to a G continuous noise. Each subject was given an otologic examination to determine their pure-tone HTL and had their personal 8-hr equivalent A-weighted noise exposure (LAeq) and full-shift noise kurtosis statistic (which is sensitive to the peaks and temporal characteristics of noise exposures) measured. For each subject, an unadjusted and kurtosis-adjusted CNE index for the years worked was created. Multiple linear regression analysis controlling for age was used to determine the relationship between CNE (unadjusted and kurtosis adjusted) and the mean HTL at 3, 4, and 6 kHz (HTL346) among the complex noise-exposed group. In addition, each subject's HTLs from 0.5 to 8.0 kHz were age and sex adjusted using Annex A (ISO-1999) to determine whether they had adjusted high-frequency noise-induced hearing loss (AHFNIHL), defined as an adjusted HTL shift of 30 dB or greater at 3.0, 4.0, or 6.0 kHz in either ear. Dose-response curves for AHFNIHL were developed separately for workers exposed to G and non-G noise using both unadjusted and adjusted CNE as the exposure matric. Results: Multiple linear regression analysis among complex exposed workers demonstrated that the correlation between HTL3,4,6 and CNE controlling for age was improved when using the kurtosis-adjusted CNE compared with the unadjusted CNE (R2 = 0.386 versus 0.350) and that noise accounted for a greater proportion of hearing loss. In addition, although dose-response curves for AHFNIHL were distinctly different when using unadjusted CNE, they overlapped when using the kurtosis-adjusted CNE. Conclusions: For the same exposure level, the prevalence of NIHL is greater in workers exposed to complex noise environments than in workers exposed to a continuous noise. Kurtosis adjustment of CNE improved the correlation with NIHL and provided a single metric for dose-response effects across different types of noise. The kurtosis-adjusted CNE may be a reasonable candidate for use in NIHL risk assessment across a wide variety of noise environments. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1RHvB4S
via IFTTT

Benefits to Speech Perception in Noise From the Binaural Integration of Electric and Acoustic Signals in Simulated Unilateral Deafness.

Objectives: This study used vocoder simulations with normal-hearing (NH) listeners to (1) measure their ability to integrate speech information from an NH ear and a simulated cochlear implant (CI), and (2) investigate whether binaural integration is disrupted by a mismatch in the delivery of spectral information between the ears arising from a misalignment in the mapping of frequency to place. Design: Eight NH volunteers participated in the study and listened to sentences embedded in background noise via headphones. Stimuli presented to the left ear were unprocessed. Stimuli presented to the right ear (referred to as the CI-simulation ear) were processed using an eight-channel noise vocoder with one of the three processing strategies. An Ideal strategy simulated a frequency-to-place map across all channels that matched the delivery of spectral information between the ears. A Realistic strategy created a misalignment in the mapping of frequency to place in the CI-simulation ear where the size of the mismatch between the ears varied across channels. Finally, a Shifted strategy imposed a similar degree of misalignment in all channels, resulting in consistent mismatch between the ears across frequency. The ability to report key words in sentences was assessed under monaural and binaural listening conditions and at signal to noise ratios (SNRs) established by estimating speech-reception thresholds in each ear alone. The SNRs ensured that the monaural performance of the left ear never exceeded that of the CI-simulation ear. The advantages of binaural integration were calculated by comparing binaural performance with monaural performance using the CI-simulation ear alone. Thus, these advantages reflected the additional use of the experimentally constrained left ear and were not attributable to better-ear listening. Results: Binaural performance was as accurate as, or more accurate than, monaural performance with the CI-simulation ear alone. When both ears supported a similar level of monaural performance (50%), binaural integration advantages were found regardless of whether a mismatch was simulated or not. When the CI-simulation ear supported a superior level of monaural performance (71%), evidence of binaural integration was absent when a mismatch was simulated using both the Realistic and the Ideal processing strategies. This absence of integration could not be accounted for by ceiling effects or by changes in SNR. Conclusions: If generalizable to unilaterally deaf CI users, the results of the current simulation study would suggest that benefits to speech perception in noise can be obtained by integrating information from an implanted ear and an NH ear. A mismatch in the delivery of spectral information between the ears due to a misalignment in the mapping of frequency to place may disrupt binaural integration in situations where both ears cannot support a similar level of monaural speech understanding. Previous studies that have measured the speech perception of unilaterally deaf individuals after CI but with nonindividualized frequency-to-electrode allocations may therefore have underestimated the potential benefits of providing binaural hearing. However, it remains unclear whether the size and nature of the potential incremental benefits from individualized allocations are sufficient to justify the time and resources required to derive them based on cochlear imaging or pitch-matching tasks. This is an open access article distributed under the Creative Commons Attribution License 4.0 (CCBY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Nf3o2a
via IFTTT

Temporal Response Properties of the Auditory Nerve in Implanted Children with Auditory Neuropathy Spectrum Disorder and Implanted Children with Sensorineural Hearing Loss.

Objective: This study aimed to (1) characterize temporal response properties of the auditory nerve in implanted children with auditory neuropathy spectrum disorder (ANSD), and (2) compare results recorded in implanted children with ANSD with those measured in implanted children with sensorineural hearing loss (SNHL). Design: Participants included 28 children with ANSD and 29 children with SNHL. All subjects used cochlear nucleus devices in their test ears. Both ears were tested in 6 children with ANSD and 3 children with SNHL. For all other subjects, only one ear was tested. The electrically evoked compound action potential (ECAP) was measured in response to each of the 33 pulses in a pulse train (excluding the second pulse) for one apical, one middle-array, and one basal electrode. The pulse train was presented in a monopolar-coupled stimulation mode at 4 pulse rates: 500, 900, 1800, and 2400 pulses per second. Response metrics included the averaged amplitude, latencies of response components and response width, the alternating depth and the amount of neural adaptation. These dependent variables were quantified based on the last six ECAPs or the six ECAPs occurring within a time window centered around 11 to 12 msec. A generalized linear mixed model was used to compare these dependent variables between the 2 subject groups. The slope of the linear fit of the normalized ECAP amplitudes (re. amplitude of the first ECAP response) over the duration of the pulse train was used to quantify the amount of ECAP increment over time for a subgroup of 9 subjects. Results: Pulse train-evoked ECAPs were measured in all but 8 subjects (5 with ANSD and 3 with SNHL). ECAPs measured in children with ANSD had smaller amplitude, longer averaged P2 latency and greater response width than children with SNHL. However, differences in these two groups were only observed for some electrodes. No differences in averaged N1 latency or in the alternating depth were observed between children with ANSD and children with SNHL. Neural adaptation measured in these 2 subject groups was comparable for relatively short durations of stimulation (i.e., 11 to 12 msec). Children with ANSD showed greater neural adaptation than children with SNHL for a longer duration of stimulation. Amplitudes of ECAP responses rapidly declined within the first few milliseconds of stimulation, followed by a gradual decline up to 64 msec after stimulus onset in the majority of subjects. This decline exhibited an alternating pattern at some pulse rates. Further increases in pulse rate diminished this alternating pattern. In contrast, ECAPs recorded from at least one stimulating electrode in six ears with ANSD and three ears with SNHL showed a clear increase in amplitude over the time course of stimulation. The slope of linear regression functions measured in these subjects was significantly greater than zero. Conclusions: Some but not all aspects of temporal response properties of the auditory nerve measured in this study differ between implanted children with ANSD and implanted children with SNHL. These differences are observed for some but not all electrodes. A new neural response pattern is identified. Further studies investigating its underlying mechanism and clinical relevance are warranted. Copyright (C) 2015 Wolters Kluwer Health, Inc. All rights reserved.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Nf3nLS
via IFTTT

William Shatner On Tinnitus

William Shatner on Tinnitus: When He Developed It

Tinnitus is a condition that affects around 50 million people in the United States. It is a condition where a person frequently experience buzzing or ringing in the ears. Tinnitus has a tendency to get worse with age. It can also be a sign of an underlying health condition, such as high blood pressure. In some cases, tinnitus occurs as the result of an injury to the ear.

Anyone can develop tinnitus. William Shatner, an actor whose career has lasted over 50 years, is one of the many people who have struggled with tinnitus. He stated that his battle with tinnitus began when he was a star on the popular 1960s show “Star Trek”.

He stated that he was filming an episode entitled “Arena.” He said that he stood very close to a special effects explosion during the filming. William has stated that he believes the sound of the explosion is what caused his tinnitus.

William Shatner on Tinnitus: His Struggle with the Condition

William Shatner struggled with tinnitus for many years. He was bothered by the constant ringing in his ears. He stated that he was tormented by tinnitus, and there were days when he felt like he could not go on because the condition was so bothersome.

William Shatner on Tinnitus: Overcoming the Condition

William Shatner stated that his life changed for the better after he discovered the American Tinnitus Foundation. He describes the foundation as being a “Ray of Light.” Williams said that he used a technique called tinnitus retraining therapy in order to overcome tinnitus. This technique involves the use of white noise.

The theory behind the use of white noise is that if you keep exposing yourself to white noise, then your brain will become accustomed to it. This training also helps your brain get adjusted to tinnitus so that you will forget that you even have it. William said that he noticed a 95 percent reduction in his symptoms after he used tinnitus retraining therapy.

Even though there are millions of people in America who have tinnitus, they often feel like they are left to suffer in silence. William Shatner has teamed up with the American Tinnitus Foundation to raise awareness about this condition and to let people know that they are not alone. The American Tinnitus Foundation is also working towards finding a cure for this condition.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1OUxOta
via IFTTT

Relationship Between Electrode-to-Modiolus Distance and Current Levels for Adults With Cochlear Implants.

Hypothesis: Electrode-to-modiolus distance is correlated with clinically programmed stimulation levels. Background: Conventional wisdom has long supposed a significant relationship between cochlear implant (CI) stimulation levels and electrode-to-modiolus distance; however, to date, no such formal investigation has been completed. Thus, the purpose of this project was to investigate the relationship between stimulation levels and electrode-to-modiolus distance. A strong correlation between the two would suggest that stimulation levels might be used to estimate electrode-to-modiolus geometry. Methods: Electrode-to-modiolus distance was determined via CT imaging using validated CI position analysis software in 137 implanted ears from the three manufacturers holding FDA approval in the United States. Analysis included 2,365 total electrodes, with 1,472 from precurved arrays. Distances were compared to clinically programmed C/M levels that were converted to charge units. Results: Mean modiolar distance with perimodiolar and lateral wall electrodes was 0.47 and 1.15 mm, respectively. Mean suprathreshold charge values were significantly different between each manufacturer. When combining all data, we found a moderate positive correlation (r = 0.367, p

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1lyaplW
via IFTTT

The Sustained-Exposure Dexamethasone Formulation OTO-104 Offers Effective Protection against Noise-Induced Hearing Loss

The otoprotective effects of OTO-104 were investigated both prior to and following acute acoustic trauma. Guinea pigs received a single intratympanic injection of OTO-104 and were assessed in a model of acute acoustic trauma. Doses of at least 2.0% OTO-104 offered significant protection against hearing loss induced by noise exposure when administered 1 day prior to trauma and up to 3 days thereafter. Otoprotection remained effective even with higher degrees of trauma. In contrast, the administration of a dexamethasone sodium phosphate solution did not protect against noise-induced hearing loss. Activation of the classical nuclear glucocorticoid and mineralocorticoid receptor pathways was required for otoprotection by OTO-104. The sustained exposure properties of OTO-104 were also superior to a steroid solution.
Audiol Neurotol 2016;21:12-21

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1OTLog8
via IFTTT

Anti CD163+, Iba1+, and CD68+ Cells in the Adult Human Inner Ear: Normal Distribution of an Unappreciated Class of Macrophages/Microglia and Implications for Inflammatory Otopathology in Humans

Hypothesis: Identification, characterization, and location of cells involved in the innate immune defense system of the human inner ear may lead to a better understanding of many otologic diseases and new treatments for hearing and balance-related disorders. Background: Many otologic disorders are thought to have, as part of their disease process, an immune component. Although resident macrophages are known to exist in the mouse inner ear, the innate immune cells in the human inner ear are, to date, unknown. Methods: Primary antibodies against CD163, Iba1, and CD68 (markers known to be specific for macrophages/microglia) were used to immunohistochemically stain celloidin embedded archival temporal bone tissue of normal individuals with no known otologic disorders other than changes associated with age. Results: Cells were positively stained throughout the temporal bone within the connective tissue and supporting cells with all three markers. They were often associated with neurons and on occasion entered the sensory cell areas of the auditory and vestibular epithelium. Conclusions: We have immunohistochemically identified an unappreciated class of cells in the normal adult inner ear consistent in staining characteristics and morphology with macrophages/microglia. As in other organ systems, it is likely these cells play an essential role in organ homeostasis that has not yet been elucidated within the ear.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8IPA
via IFTTT

A Systematic Review of the Diagnostic Value of CT Imaging in Diagnosing Otosclerosis

Objective: To evaluate the diagnostic value of computed tomography (CT) in detecting otosclerosis in patients with conductive hearing loss and a clinical suspicion of otosclerosis. Data Sources: PubMed, Embase, and the Cochrane Library. Study Selection: A systematic search was conducted. Studies reporting original study data were included. Data Extraction: Relevance and risk of bias of the selected articles were assessed. Studies with low relevance, high risk of bias, or both were excluded. Prevalences, sensitivities, specificities, and post-test probabilities were extracted from the included articles. Data Synthesis: Seven studies characterized by a moderate to high relevance and moderate to low risk of bias were included for data extraction. The prevalence of otosclerosis was high (up to 100%) in the majority of the included studies. In those studies with a high prevalence of disease, both positive and negative post-test probabilities were (relatively) high: 99% and between 51% and 67% respectively. In one study with a low prevalence of disease (9%), both positive and negative post-test probabilities were low (23% and 3% respectively). Overall, reported sensitivities ranged between 60% and 95%. Conclusion: Preoperative CT has little to add in establishing otosclerosis and may not be necessary to confirm the diagnosis. We would recommend reserving CT for those patients with suspected additional abnormalities, for specific preoperative planning, or out of legal necessity.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8IPy
via IFTTT

Cochlear Implantation in the Setting of Cochlear Ossification as Sequela of Malarial Meningitis

No abstract available

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8Ize
via IFTTT

Progressively Recovering Auditory Brainstem Response in a Cochlear-implanted Child After Meningitis: A Case Report

Objective: I describe the case of an 8-year-old boy who developed meningitis several years after implantation and how electrically evoked auditory brainstem response (EABR) is used in the assessment of his hearing performance after recovery. Patient: An 8-year-old boy stopped using both his cochlear implants because of streptococcal meningitis accompanied with acute otitis media on the left ear. After recovery his hearing was quickly restored on the right ear, but he complained of not hearing well on the left ear. Intervention: Diagnostic. Main Outcome Measure: EABRs were measured on both ears 2 months after meningitis offset. Testing was repeated on the left ear 12 and 18 months after the first session. Responses were evoked by apical, mid-array, and basal electrodes. Results: At initial testing EABRs were normal on the right ear. They were absent on the left ear for the apical electrode and present but with delayed wave latencies for the middle and basal electrodes. At the second and third sessions, EABRs were present for all electrodes and wave eV latencies were shorter. The stimulus level needed to evoke an EABR was considerably reduced on all electrodes from the first to the third session. There was good agreement between these findings and the subjective feedback from the patient. Conclusion: EABR provided valuable information throughout the patient's hearing recovery. Its use should be considered in difficult patients, especially those who cannot give feedback.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Qheo2R
via IFTTT

Responses to Drs. Kaski and Bronstein and Dr. Crane

No abstract available

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8KHm
via IFTTT

Speech Intelligibility in Noise With a Pinna Effect Imitating Cochlear Implant Processor

Objective: To evaluate the speech intelligibility in noise with a new cochlear implant (CI) processor that uses a pinna effect imitating directional microphone system. Study Design: Prospective experimental study. Setting: Tertiary referral center. Patients: Ten experienced, unilateral CI recipients with bilateral severe-to-profound hearing loss. Intervention: All participants performed speech in noise tests with the Opus 2 processor (omnidirectional microphone mode only) and the newer Sonnet processor (omnidirectional and directional microphone mode). Main Outcome Measure: The speech reception threshold (SRT) in noise was measured in four spatial settings. The test sentences were always presented from the front. The noise was arriving either from the front (S0N0), the ipsilateral side of the CI (S0NIL), the contralateral side of the CI (S0NCL), or the back (S0N180). Results: The directional mode improved the SRTs by 3.6 dB (p 

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Qheo2N
via IFTTT

Characteristics of Wax Occlusion in the Surgical Repair of Superior Canal Dehiscence in Human Temporal Bone Specimens

Hypothesis: Superior canal dehiscence (SCD) repair using surgical bone wax may result in variable outcomes if large wax volumes are applied. Background: SCD is a disorder characterized by a pathologic defect in the bony labyrinth of the superior semicircular canal (SSC), resulting in vestibular and/or auditory symptoms. Repair of SCD using bone wax can provide symptomatic relief, but surgical outcomes are variable. These observations may be associated with the inconsistency in the position and extension of intralabyrinthine bone wax during surgical repair. Methods: A pathological model of SCD was created using cadaveric human temporal bones and a microdrill. Defects in the arcuate eminence 0.5 to 3.5 mm in length were repaired by surgical occlusion with bone wax. The volume of wax used in the repair was quantified. The position of bone wax was evaluated by direct visualization and imaging (computed tomography [CT]). To visualize wax on CT, specimens were repaired using radiopaque wax. Results: Exceedingly small volumes of bone wax (3.0–5.0 mm2) reliably occluded the canal lumen. Multiple wax applications resulted in extension into the common crus and ampulla. The length of this extension was related to the number of applications. Conclusions: Repair of SCD with bone wax occludes the bony defect completely in most patients. Wax can extend along the lumen of the superior canal beyond the limits of the dehiscence to reach the sensory neuroepithelium of the vestibular end organs. Limiting the number of wax applications is essential to avoid inadvertent injury to the delicate neurosensory systems.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhenMv
via IFTTT

Early Bimodal Stimulation Benefits Language Acquisition for Children With Cochlear Implants

Hypothesis: Adding a low-frequency acoustic signal to the cochlear implant (CI) signal (i.e., bimodal stimulation) for a period of time early in life improves language acquisition. Background: Children must acquire sensitivity to the phonemic units of language to develop most language-related skills, including expressive vocabulary, working memory, and reading. Acquiring sensitivity to phonemic structure depends largely on having refined spectral (frequency) representations available in the signal, which does not happen with CIs alone. Combining the low-frequency acoustic signal available through hearing aids with the CI signal can enhance signal quality. A period with this bimodal stimulation has been shown to improve language skills in very young children. This study examined whether these benefits persist into childhood. Methods: Data were examined for 48 children with CIs implanted under age 3 years, participating in a longitudinal study. All children wore hearing aids before receiving a CI, but upon receiving a first CI, 24 children had at least 1 year of bimodal stimulation (Bimodal group), and 24 children had only electric stimulation subsequent to implantation (CI-only group). Measures of phonemic awareness were obtained at second and fourth grades, along with measures of expressive vocabulary, working memory, and reading. Results: Children in the Bimodal group generally performed better on measures of phonemic awareness, and that advantage was reflected in other language measures. Conclusions: Having even a brief period of time early in life with combined electric-acoustic input provides benefits to language learning into childhood, likely because of the enhancement in spectral representations provided.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8Iiy
via IFTTT

Why no Unilateral Vestibular Atelectasis?

No abstract available

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8KqO
via IFTTT

Relationship Between Electrode-to-Modiolus Distance and Current Levels for Adults With Cochlear Implants

Hypothesis: Electrode-to-modiolus distance is correlated with clinically programmed stimulation levels. Background: Conventional wisdom has long supposed a significant relationship between cochlear implant (CI) stimulation levels and electrode-to-modiolus distance; however, to date, no such formal investigation has been completed. Thus, the purpose of this project was to investigate the relationship between stimulation levels and electrode-to-modiolus distance. A strong correlation between the two would suggest that stimulation levels might be used to estimate electrode-to-modiolus geometry. Methods: Electrode-to-modiolus distance was determined via CT imaging using validated CI position analysis software in 137 implanted ears from the three manufacturers holding FDA approval in the United States. Analysis included 2,365 total electrodes, with 1,472 from precurved arrays. Distances were compared to clinically programmed C/M levels that were converted to charge units. Results: Mean modiolar distance with perimodiolar and lateral wall electrodes was 0.47 and 1.15 mm, respectively. Mean suprathreshold charge values were significantly different between each manufacturer. When combining all data, we found a moderate positive correlation (r = 0.367, p 

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Qhembc
via IFTTT

Response to Colebatch and Rosengren: “Safe Levels of Acoustic Stimulation for Vemps” Comment on “Sudden Bilateral Hearing Loss After Cervical and Ocular Vestibular Evoked Myogenic Potentials”

No abstract available

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8I2e
via IFTTT

Cost–Utility of Bilateral Versus Unilateral Cochlear Implantation in Adults: A Randomized Controlled Trial

Objective: To study the cost–utility of simultaneous bilateral cochlear implantation (CI) versus unilateral CI. Study Design: Randomized controlled trial (RCT). Setting: Five tertiary referral centers. Patients: Thirty-eight postlingually deafened adults eligible for cochlear implantation. Interventions: A cost–utility analysis was performed from a health insurance perspective. Main Outcome Measures: Utility was assessed using the HUI3, TTO, VAS on hearing, VAS on general health and EQ-5D. We modeled the incremental cost per quality-adjusted life year (QALY) of unilateral versus bilateral CI over periods of 2, 5, 10, 25 years, and actual life-expectancy. Results: Direct costs for unilateral and bilateral CI were €43,883 ± €11,513(SD) and €87,765 ± €23,027(SD) respectively. Annual costs from the second year onward were €3,435 ± €1,085(SD) and €6,871 ± €2,169(SD), respectively. A cost–utility analysis revealed that a second implant became cost-effective after a 5- to 10-year period, based on the HUI3, TTO, and VAS on hearing. Conclusion: This is the first study that describes a cost–utility analysis to compare unilateral with simultaneous bilateral CI in postlingually deafened adults, using a multicenter RCT. Compared with accepted societal willingness-to-pay thresholds, simultaneous bilateral CI is a cost-effective treatment for patients with a life expectancy of 5–10 years or longer.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhelUN
via IFTTT

Systematic Review: Incidence and Course of Hearing Loss Caused by Bacterial Meningitis: In Search of an Optimal Timed Audiological Follow-up

Objective: The objective of this study was to clarify the incidence and course of hearing loss after bacterial meningitis to optimize the audiological follow-up. Data Sources: The databases Embase, Medline (OvidSP), Web-of-science, Scopus, Cinahl, Cochrane, PubMed publisher, and Google Scholar were used. Only articles written in English were included. Study Selection: Articles published from 1985 until March 2015 describing the incidence, risk factors, or course of hearing loss after meningitis were used. Data Extraction: The quality of the studies was assessed on three aspects: quality of audiometry, number of patients, and methodological quality. Data Synthesis: For each publication, data were entered in spreadsheet software for analysis. The data were analyzed and interpreted using best evidence synthesis. Conclusions: The overall quality of the included studies was poor. A major drawback was the quality of the (description of) audiometry, severity, and timing of hearing loss. A systematic review of the literature showed an incidence of hearing loss (>25 ± 5 dB) of 14% and an incidence of 5% for profound hearing loss (>90 dB). Patients with initial normal hearing after meningitis showed stable normal hearing over time. However, initial hearing loss related to meningitis can improve or deteriorate over time. We therefore recommend early audiological testing of all patients who suffered bacterial meningitis. However, long-term audiological follow-up is only needed for patients with early onset hearing loss and not for patients with normal hearing at the first hearing test.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhelUL
via IFTTT

Outcomes After Cochlear Implantation in the Very Elderly

Objective: To evaluate the outcomes after cochlear implantation (CI) in the elderly population, with a particular emphasis on perioperative complications, dizziness, and speech perception outcomes. Study Design: A retrospective cohort study of elderly cochlear implant patients. Setting: Tertiary referral center (Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne). Patients: All patients aged 75 and above at the time of first cochlear implant (N = 150). Comparison was made between groups aged 85+ to 80–84, and 75–79. Interventions: All patients received Nucleus devices (either CI512 or CI24RE(CA)). Main Outcome Measures: Speech recognition scores both pre- and postimplantation, symptomatic dizziness and effects upon independent living after surgery, and the incidence of perioperative medical and surgical complications. Complications were classified as major (intrinsic device failure, device migration, extracochlear insertion, meningitis, surgical site infection requiring reoperation, wound breakdown, permanent facial nerve paralysis) and minor (tinnitus, transient facial nerve palsy, facial nerve stimulation, taste disturbance, delayed wound healing). Results: All three cohorts had poor preoperative speech perception. There was significant improvement in postoperative word scores at 3 and 12 months across all groups. There was no statistically significant difference between the three cohorts in terms of speech recognition outcomes at 3 and 12 months. After surgery, more than 20% of patients at all ages experienced transient imbalance, although the incidence did not differ significantly between age groups (p = 0.71). In total, there were 13 major complications in 7 patients (4.7%), and 28 minor complications in 25 patients (16.7%). Conclusion: Postoperative disequilibrium was commonly observed in this elderly population, yet patients still benefited with improved speech perception after cochlear implantation. Elderly patients can benefit from cochlear implantation, and age should not be a limitation for CI surgery. Cochlear implantation can be done safely and provides significant patient benefits.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8Kab
via IFTTT

A Neuromonitoring Approach to Facial Nerve Preservation During Image-guided Robotic Cochlear Implantation

Hypothesis: A multielectrode probe in combination with an optimized stimulation protocol could provide sufficient sensitivity and specificity to act as an effective safety mechanism for preservation of the facial nerve in case of an unsafe drill distance during image-guided cochlear implantation. Background: A minimally invasive cochlear implantation is enabled by image-guided and robotic-assisted drilling of an access tunnel to the middle ear cavity. The approach requires the drill to pass at distances below 1 mm from the facial nerve and thus safety mechanisms for protecting this critical structure are required. Neuromonitoring is currently used to determine facial nerve proximity in mastoidectomy but lacks sensitivity and specificity necessaries to effectively distinguish the close distance ranges experienced in the minimally invasive approach, possibly because of current shunting of uninsulated stimulating drilling tools in the drill tunnel and because of nonoptimized stimulation parameters. To this end, we propose an advanced neuromonitoring approach using varying levels of stimulation parameters together with an integrated bipolar and monopolar stimulating probe. Materials and Methods: An in vivo study (sheep model) was conducted in which measurements at specifically planned and navigated lateral distances from the facial nerve were performed to determine if specific sets of stimulation parameters in combination with the proposed neuromonitoring system could reliably detect an imminent collision with the facial nerve. For the accurate positioning of the neuromonitoring probe, a dedicated robotic system for image-guided cochlear implantation was used and drilling accuracy was corrected on postoperative microcomputed tomographic images. Results: From 29 trajectories analyzed in five different subjects, a correlation between stimulus threshold and drill-to-facial nerve distance was found in trajectories colliding with the facial nerve (distance 95%) at distances to the facial nerve below 0.5 mm. However, reduction in stimulus threshold to 0.3 mA or lower resulted in a decrease of facial nerve distance detection range below 0.1 mm (>95% sensitivity). Subsequent histopathology follow-up of three representative cases where the neuromonitoring system could reliably detect a collision with the facial nerve (distance

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhenvO
via IFTTT

Lamb Temporal Bone as a Surgical Training Model of Round Window Cochlear Implant Electrode Insertion

Objective: The preservation of residual hearing in cochlear implantation opens the door for optimal functional results. This atraumatic surgical technique requires training; however, the traditional human cadaveric temporal bones have become less available or unattainable in some institutions. This study investigates the suitability of an alternative model, using cadaveric lamb temporal bone, for surgical training of atraumatic round window electrode insertion. Intervention: A total of 14 lamb temporal bones were dissected for cochlear implantation by four surgeons. After mastoidectomy, visualization, and drilling of the round window niche, an atraumatic round window insertion of a Medel Flex24 electrode was performed. Electrode insertion depth and position were verified by computed tomography scans. Main Outcome Measure: All cochleas were successfully implanted using the atraumatic round window approach; however, surgical access through the mastoid was substantially different when compared human anatomy. The mean number of intracochlear electrode contacts was 6.5 (range, 4–11) and the mean insertion depth 10.4 mm (range, 4–20 mm), which corresponds to a mean angular perimodiolar insertion depth of 229 degrees (range 67–540°). Full insertion of the electrode was not possible because of the smaller size of the lamb cochlea in comparison to that of the human. Conclusion: The lamb temporal bone model is well suited as a training model for atraumatic cochlear implantation at the level of the round window. The minimally pneumatized mastoid as well as the smaller cochlea can help prepare a surgeon for difficult cochlear implantations. Because of substantial differences to human anatomy, it is not an adequate training model for other surgical techniques such as mastoidectomy and posterior tympanotomy as well as full electrode insertion.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhenvM
via IFTTT

Birth and Evolution of Chiselling and Drilling Techniques for Removing Ear Canal Exostoses

The main surgical techniques used to remove ear canal exostoses are drilling and/or, chiselling. The aim of this study was to identify the origins and subsequent evolution of, the surgical removal of ear canal exostoses in the 19th century. A critical review and, compilation of primary and secondary historical sources was conducted. Two techniques for removal of exostoses were developed in the latter part of the 19th century and have largely remained unchanged. This demonstrates the importance of that era in the history of ear surgery.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhelUA
via IFTTT

Mastoid Dimensions in Children and Young Adults: Consequences for the Geometry of Transcutaneous Bone-Conduction Implants

Objectives: Bone-conduction implants (BCI) are available for adults and children who are aged 5 years or more. Because a transcutaneous bone-conduction implant introduced in 2013 does not completely fit into all adult mastoids, we investigated mastoid dimensions and the possibility of fitting the implant in children. Design: Computed tomography scans of 151 mastoids from 80 children and young adolescents from the age of 5 months to 20 years and 52 control mastoids from 33 adults were retrospectively analyzed. After three-dimensional reconstruction, mastoid volume was measured. The chances of fitting the Bonebridge or a novel BCI were determined as a function of age. Implant diameter and implantation depths were virtually varied to identify the most advantageous dimensions for reducing the minimum age for implantation. Results: Mastoid volume increased to 13.8 ml in female and 16.4 ml in male adult mastoids at ages 18.9 years (male) and 19.0 years (female). Without compromising the middle fossa dura or the sinus and without lifts, the Bonebridge implant fit in 81% of male adult mastoids and 77% of the female adult mastoids. For children, the 50% chance of fitting a Bonebridge in the mastoids was reached at age 12 years; with a protrusion of 4 mm (4-mm lifts), this age was reduced to >6 years. The novel BCI fit in 100% of male and 94% of female adult mastoids. Conclusions: Casing diameter is the most limiting factor for Bonebridge implantation in children. A modified implant casing with a truncated cone and reduced diameter and volume would increase the number of hearing impaired children who can be rehabilitated with a Bonebridge implant. Radiological planning for Bonebridge implantation is necessary in all children.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Ok8JTH
via IFTTT

Patients with Vestibular Loss, Tullio Phenomenon, and Pressure-induced Nystagmus: Vestibular Atelectasis?

No abstract available

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1QhenvH
via IFTTT

Transcanal Endoscopic Management of Cerebrospinal Fluid Otorrhea Secondary to Congenital Inner Ear Malformations

Objective: To describe the feasibility of using a transcanal endoscopic approach for management of cerebrospinal leaks secondary to congenital inner ear malformations. Patients: Two pediatric patients with congenital inner ear malformations and concurrent cerebrospinal fluid leakage. Intervention: A stapedectomy was performed and the inner ear was packed with temporalis muscle using a transcanal endoscopic approach. Main Outcome Measure: Cessation of cerebrospinal fluid leakage from the inner ear to the middle ear. Results: An otic capsule malformation with a modiolar defect as well as a defect in the stapes footplate was noted in both patients. Successful repair of cerebrospinal fluid otorrhea was achieved in both patients using a minimally invasive transcanal endoscopic approach. One patient developed postoperative meningitis that was successfully managed with antibiotics. Conclusions: Cerebrospinal fluid otorrhea from an inner ear malformation often presents as persistent clear otorrhea after tympanostomy tube placement or recurrent meningitis as was the case in the two patients in this series. A minimally invasive transcanal endoscopic approach is a viable alternative to manage this unique entity.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1NXxieP
via IFTTT

Maximum entropy inference of seabed attenuation parameters using ship radiated broadband noise

The received acoustic field generated by a single passage of a research vessel on the New Jersey continental shelf is employed to infer probability distributions for the parameter values representing the frequency dependence of the seabed attenuation and the source levels of the ship. The statistical inference approach employed in the analysis is a maximum entropy methodology. The average value of the error function, needed to uniquely specify a conditional posterior probability distribution, is estimated with data samples from time periods in which the ship-receiver geometry is dominated by either the stern or bow aspect. The existence of ambiguities between the source levels and the environmental parameter values motivates an attempt to partially decouple these parameter values. The main result is the demonstration that parameter values for the attenuation (α and the frequency exponent), the sediment sound speed, and the source levels can be resolved through a model space reduction technique. The results of this multi-step statistical inference developed for ship radiated noise is then tested by processing towed source data over the same bandwidth and source track to estimate continuous wave source levels that were measured independently with a reference hydrophone on the tow body.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1IX9ujH
via IFTTT

High frequency source localization in a shallow ocean sound channel using frequency difference matched field processinga)

Matched field processing(MFP) is an established technique for source localization in known multipath acoustic environments. Unfortunately, in many situations, particularly those involving high frequency signals, imperfect knowledge of the actual propagation environment prevents accurate propagation modeling and source localization via MFP fails. For beamforming applications, this actual-to-model mismatch problem was mitigated through a frequency downshift, made possible by a nonlinear array-signal-processing technique called frequency difference beamforming [Abadi, Song, and Dowling (2012). J. Acoust. Soc. Am. 132, 3018–3029]. Here, this technique is extended to conventional (Bartlett) MFP using simulations and measurements from the 2011 Kauai Acoustic Communications MURI experiment (KAM11) to produce ambiguity surfaces at frequencies well below the signal bandwidth where the detrimental effects of mismatch are reduced. Both the simulation and experimental results suggest that frequency difference MFP can be more robust against environmental mismatch than conventional MFP. In particular, signals of frequency 11.2 kHz–32.8 kHz were broadcast 3 km through a 106-m-deep shallow oceansound channel to a sparse 16-element vertical receiving array. Frequency difference MFP unambiguously localized the source in several experimental data sets with average peak-to-side-lobe ratio of 0.9 dB, average absolute-value range error of 170 m, and average absolute-value depth error of 10 m.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/21RBe4Z
via IFTTT

An active mute for the trombone

A mute is a device that is placed in the bell of a brass instrument to alter its sound. However, when a straight mute is used with a brass instrument, the frequencies of its first impedance peaks are slightly modified, and a mistuned, extra impedance peak appears. This peak affects the instrument's playability, making some lower notes difficult or impossible to produce when playing at low dynamic levels. To understand and suppress this effect, an active mute with embedded microphone and speaker has been developed. A control loop with gain and phase shifting is used to control the damping and frequency of the extra impedance peak. The stability of the controlled system is studied and then the effect of the control on the input impedance and radiated sound of the trombone is investigated. It is shown that the playability problem results from a decrease in the input impedance magnitude at the playing frequency, caused by a trough located on the low frequency side of the extra impedance peak. When the extra impedance peak is suppressed, the playability of the note is restored. Meanwhile, when the extra impedance peak is moved in frequency, the playability problem position is shifted as well.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/21RBdOx
via IFTTT

Numerical analyses of the sound absorption of cylindrical microperforated panel space absorbers with cores

Microperforated panels (MPPs) are next-generation absorptionmaterials because they can provide wideband sound absorption without fibrous materials and can be composed of diverse materials to meet global environmental demands. The fundamental absorbing mechanism is Helmholtz-resonance absorption due to perforations and an air cavity. MPPs are typically backed by rigid flat walls, but to reduce the restrictions on the MPP absorber properties, one of the authors has proposed MPP space sound absorbers without backing structures, including three-dimensional cylindrical microperforated panel space absorbers (CMSAs). Advantages of MPPs without backing structures are design flexibility and ease of use. Besides, the absorptioncharacteristics of a CMSA with a core, which has a rigid cylindrical core inside the CMSA, have been experimentally tested, but a method to predict the absorptioncharacteristics is necessary to design CMSAs with cores. Herein the two-dimensional combined Helmholtz integral formulation method is employed, and its prediction accuracy is evaluated by comparing the measured and predicted absorptioncharacteristics of a CMSA with a core. Furthermore, a parametric study with regard to the core size is carried out to investigate the transition of the absorbing mechanism.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1IX9wIm
via IFTTT

Maximum entropy inference of seabed attenuation parameters using ship radiated broadband noise

The received acoustic field generated by a single passage of a research vessel on the New Jersey continental shelf is employed to infer probability distributions for the parameter values representing the frequency dependence of the seabed attenuation and the source levels of the ship. The statistical inference approach employed in the analysis is a maximum entropy methodology. The average value of the error function, needed to uniquely specify a conditional posterior probability distribution, is estimated with data samples from time periods in which the ship-receiver geometry is dominated by either the stern or bow aspect. The existence of ambiguities between the source levels and the environmental parameter values motivates an attempt to partially decouple these parameter values. The main result is the demonstration that parameter values for the attenuation (α and the frequency exponent), the sediment sound speed, and the source levels can be resolved through a model space reduction technique. The results of this multi-step statistical inference developed for ship radiated noise is then tested by processing towed source data over the same bandwidth and source track to estimate continuous wave source levels that were measured independently with a reference hydrophone on the tow body.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1IX9ujH
via IFTTT

High frequency source localization in a shallow ocean sound channel using frequency difference matched field processinga)

Matched field processing(MFP) is an established technique for source localization in known multipath acoustic environments. Unfortunately, in many situations, particularly those involving high frequency signals, imperfect knowledge of the actual propagation environment prevents accurate propagation modeling and source localization via MFP fails. For beamforming applications, this actual-to-model mismatch problem was mitigated through a frequency downshift, made possible by a nonlinear array-signal-processing technique called frequency difference beamforming [Abadi, Song, and Dowling (2012). J. Acoust. Soc. Am. 132, 3018–3029]. Here, this technique is extended to conventional (Bartlett) MFP using simulations and measurements from the 2011 Kauai Acoustic Communications MURI experiment (KAM11) to produce ambiguity surfaces at frequencies well below the signal bandwidth where the detrimental effects of mismatch are reduced. Both the simulation and experimental results suggest that frequency difference MFP can be more robust against environmental mismatch than conventional MFP. In particular, signals of frequency 11.2 kHz–32.8 kHz were broadcast 3 km through a 106-m-deep shallow oceansound channel to a sparse 16-element vertical receiving array. Frequency difference MFP unambiguously localized the source in several experimental data sets with average peak-to-side-lobe ratio of 0.9 dB, average absolute-value range error of 170 m, and average absolute-value depth error of 10 m.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/21RBe4Z
via IFTTT

An active mute for the trombone

A mute is a device that is placed in the bell of a brass instrument to alter its sound. However, when a straight mute is used with a brass instrument, the frequencies of its first impedance peaks are slightly modified, and a mistuned, extra impedance peak appears. This peak affects the instrument's playability, making some lower notes difficult or impossible to produce when playing at low dynamic levels. To understand and suppress this effect, an active mute with embedded microphone and speaker has been developed. A control loop with gain and phase shifting is used to control the damping and frequency of the extra impedance peak. The stability of the controlled system is studied and then the effect of the control on the input impedance and radiated sound of the trombone is investigated. It is shown that the playability problem results from a decrease in the input impedance magnitude at the playing frequency, caused by a trough located on the low frequency side of the extra impedance peak. When the extra impedance peak is suppressed, the playability of the note is restored. Meanwhile, when the extra impedance peak is moved in frequency, the playability problem position is shifted as well.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/21RBdOx
via IFTTT

Numerical analyses of the sound absorption of cylindrical microperforated panel space absorbers with cores

Microperforated panels (MPPs) are next-generation absorptionmaterials because they can provide wideband sound absorption without fibrous materials and can be composed of diverse materials to meet global environmental demands. The fundamental absorbing mechanism is Helmholtz-resonance absorption due to perforations and an air cavity. MPPs are typically backed by rigid flat walls, but to reduce the restrictions on the MPP absorber properties, one of the authors has proposed MPP space sound absorbers without backing structures, including three-dimensional cylindrical microperforated panel space absorbers (CMSAs). Advantages of MPPs without backing structures are design flexibility and ease of use. Besides, the absorptioncharacteristics of a CMSA with a core, which has a rigid cylindrical core inside the CMSA, have been experimentally tested, but a method to predict the absorptioncharacteristics is necessary to design CMSAs with cores. Herein the two-dimensional combined Helmholtz integral formulation method is employed, and its prediction accuracy is evaluated by comparing the measured and predicted absorptioncharacteristics of a CMSA with a core. Furthermore, a parametric study with regard to the core size is carried out to investigate the transition of the absorbing mechanism.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1IX9wIm
via IFTTT

Results of the first universal newborn hearing screening in Algeria

Farid Boudjenah, Mokhtar Hasbellaoui, Omar Zemirli

Advanced Arab Academy of Audio-Vestibulogy Journal 2015 2(2):54-58

Introduction Hearing loss is the most common congenital pathology at birth. Its prevalence increases during the infant period, especially in children at risk. The application of hearing screening in three stages with follow-up of children at risk of developing hearing loss allows to optimize the screening. Goals The aim of this study was to evaluate the prevalence of hearing loss in the neonatal population and identify newborns at risk and to investigate the best way to support infants with such disability from screening to rehabilitation. Materials and methods This prospective study was conducted over a period of 22 months from June 2011 to March 2013, using a systematic screening for deafness in a high-birth-level maternity unit. Results Over a period of 22 months, 17 912 live newborn were born in the maternity ward. The application of screening for deafness at birth allowed us to screen 15 382 newborns, with a coverage rate of 85.9%. We chose a three-stage screening protocol. In the first stage, 15 382 newborns were screened by means of analysis of distortion product of otoacoustic emissions (DPOAE). The screening was negative (presence of DPOAE and absence of hearing loss) in 13 467 newborns, and it was positive (absence of DPOAE and a possibility of hearing loss) for 1915 newborns who were addressed to the second stage of the screening protocol for the analysis of DPOAE again after 1 month of birth. In this second stage of screening, 1516 infants were screened in the ENT Department and 399 infants were lost to follow-up. After the second stage of the screening, 76 infants were addressed to the third stage of the screening protocol, which is also called stage of diagnosis. In this last step, 14 children were lost to follow-up and 62 infants were tested for hearing threshold using analysis of auditory brainstem response. Finally, after verification of the results obtained in the third stage using behavioral audiometry and impedance, 49 children showed hearing loss with a hearing threshold greater than 30 dB. The prevalence of neonatal hearing loss in the maternity unit was 3.2%. There were 27 male and 22 female patients, of whom 29 had bilateral hearing loss and 20 children had unilateral hearing loss. In contrast, the study of the risk factors of hearing loss allowed us to identify those who are present among the detected newborns and to calculate the prevalence of hearing loss among newborns admitted in the neonatal ICU, which was 2.14%. The risk factors most associated with deafness are infections with cytomegalovirus and rubella, damage to the nervous system and craniofacial malformations. The rehabilitation of hearing is based on speech rehabilitation and the use a hearing aid, either conventional prosthesis or cochlear implant. Conclusion Newborn hearing screening using a three-stage protocol is possible. It allows to detect hearing loss earlier to initiate early hearing and language rehabilitation, the only way to guarantee alignment of children born with hearing impairment or with contracted hearing loss during the neonatal period with their peers with normal hearing.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Z0ZKOI
via IFTTT

Neuroplastic changes in musician's brain: A review

Himanshu Kumar Sanju

Advanced Arab Academy of Audio-Vestibulogy Journal 2015 2(2):43-44

Neuroplasticity refers to any change or modification in the central nervous system because of any adaptation or experience to environmental demands. Musical training and experience can lead to neuroplasticity because music requires cognitive and neural challenges that need accurate and precise timing of many actions, exact interval control of pitch not involved in language, and various different way of producing sound. It was also reported that a musician's brain is best to study neuroplastic changes. Therefore, the current review explored studies related to neuroplasticity in musicians' brains. Various database such as Medline, PubMed, Google, and Google Scholar were searched for the reference to neuroplasticity in musicians.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1Z0ZKOG
via IFTTT

Pharmacotherapy of vestibular disorders

Hesham Mahmoud Samy

Advanced Arab Academy of Audio-Vestibulogy Journal 2015 2(2):39-42

Dizziness and vertigo are symptoms directly related to dysfunction of the vestibular system. Imbalance is the most common complaint, especially in the elderly population, which results in falls and mobility restriction. There is no common drug for the management of balance disorders. Medications should be prescribed carefully, and according to clear diagnosis. The pharmacotherapy of vertigo can be optimized with detailed knowledge of the drugs effective in vertigo, as well as their side effects. A thorough review of the literature reveals that there is a significant lack of information concerning the real utility of different drugs used in clinical practice. This article discusses the pharmacological options that are available for the treatment of balance disorders, along with some recent advances.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1XYMbCi
via IFTTT

Vestibular evoked myogenic potentials and video head impulse tests in different stages of Meniere's disease

Doaa M Elmoazen, Ossama A Sobhy, Fathy Abd Elbaky

Advanced Arab Academy of Audio-Vestibulogy Journal 2015 2(2):45-53

Introduction Meniere's disease (MD) is characterized by intermittent episodes of vertigo, fluctuating sensorineural hearing loss, tinnitus, and aural pressure. Histopathologically, endolymphatic hydrops is seen initially in the cochlear duct and the saccule; with the progression of the disease, subsequent affection of the utricle and semicircular canals (SCC) occur. Objectives The aim of this study was to assess the function of the saccule, the utricle, and the three SCCs using cervical vestibular evoked myogenic potential (cVEMP), ocular vestibular evoked myogenic potential (oVEMP), and video head impulse test (vHIT), respectively, in Meniere's patients and to correlate the findings with the different stages of MD. Patients and methods Forty patients diagnosed with unilateral definite MD according to the American Academy of Otolaryngology and Head and Neck Surgery's 1995 criteria [AAO-HNS (1995) criteria] were tested. They were divided into four subgroups based on the stage of MD using the average of 500, 1000, 2000, and 3000 Hz pure-tone thresholds of the worst documented audiogram during the 6-month interval before examination. A control group of 40 healthy age-matched adults were equally divided into four corresponding subgroups based on their pure-tone average. In all, 500 and 1000 Hz tone burst air conduction cVEMP and oVEMP tests, bithermal caloric test, and vHIT for all SCCs were recorded for both groups. Results The results of this study showed that the highest prevalence of abnormalities in Meniere's patients were seen in the pure tone average (PTA) (85%), followed by cVEMP (72.5%) and oVEMP (67.5%). Caloric test abnormalities follow with a lower prevalence of 32.5%. The vHIT presented the lowest prevalence of abnormalities, with 20% in the lateral canal, 7.5% in the anterior, and 5% in the posterior canal. This pattern of abnormality is in agreement with the reported pattern of hydrops formation in the vestibular system. Conclusion The findings of the current study suggest that with the advancement in the stage of MD consequent abnormal cVEMP, oVEMP, caloric, and vHIT responses occur following the histopathological evidence of progression of the disease from the saccule up to the SCCs.

from #Audiology via xlomafota13 on Inoreader http://ift.tt/1XYMbCk
via IFTTT