Descending stairs: Good or bad task to discriminate women with patellofemoral pain?

Publication date: September 2018

Source: Gait & Posture, Volume 65

Author(s): Aline de Almeida Novello, Silvio Garbelotti, Nayra Deise dos Anjos Rabelo, André Nogueira Ferraz, André Serra Bley, João Carlos Ferrari Correa, Fabiano Politti, Paulo Roberto Garcia Lucareli

Abstract

Background

There is no consensus on kinematics alterations during descending stairs in females with patellofemoral pain (PFP). In addition, there are no studies that have evaluated the three dimensional kinematics of the trunk, pelvis, hip, knee, and ankle using a multi-segmental model of the foot simultaneously during this task in patients with PFP and evaluated the subphases of stair descent. The objectives of this study were to compare the three dimensional kinematics of the trunk, pelvis, and lower limbs during different subphases of stair descent and identify the discriminatory capacity of the kinematic variables among women with PFP and healthy women.

Methods

In this cross-sectional study, thirty-four women with PFP and thirty-four pain free women between 18 and 35 years-old were submitted to three-dimensional kinematic evaluation during stair descent.

Results

It was observed that kinematic differences between the groups occurred in the first double support phase of the stair descent, with the variables of internal rotation of the hindfoot in relation to the tibia in the initial contact (2.1°; sensitivity = 68.6%, specificity = 61.8%) and contralateral pelvic drop in load response (1.3°, sensitivity = 65.7%, specificity = 63.7%) presenting the best ability to discriminate women with and without PFP.

Conclusion

Our results suggest that kinematic changes during stair descent should be used with caution during the evaluation and decision-making process in women with PFP.

from #Audiology via ola Kala on Inoreader https://ift.tt/2lS9SNE
via IFTTT

Graded forward and backward walking at a matched intensity on cardiorespiratory responses and postural control

Publication date: September 2018

Source: Gait & Posture, Volume 65

Author(s): Kathleen S. Thomas, Macon Hammond, Meir Magal

Abstract

Background

While several studies compare backward walking (BW) and forward walking (FW) in terms of heart rate (HR) and rating of perceived exertion (RPE), workload (VO₂) was not matched to control for intensity levels (Hooper et al. [1]). Moreover, acute effects of inclined BW on postural control and ankle musculature has not been investigated. This study was designed to compare cardiovascular, metabolic and perceptual responses, changes in center of pressure (COP) motion, and muscle activation of tibialis anterior (TA) and gastrocnemius (GM) to control quiet stance posture immediately following inclined BW and FW at a matched intensity.

Methods

Seventeen healthy young adults completed three lab sessions 7–14 days apart. Session one, maximal oxygen consumption (VO_2max) was measured using open-circuit spirometry for each participant. Session two, participants performed BW for 15-min. Session three, participants performed FW for 15-min at matched intensity of BW. Surface electromyography (SEMG) measured the muscular activity of the TA and GM during bilateral stance on a force plate for 30 s prior to and immediately following BW and FW under both eyes open (EO), and eyes closed (EC) conditions.

Results

HR, VCO₂, RER and RPE were significantly greater during BW compared to FW. Increased muscle activation and COP motion was elicited immediately following BW compared to FW under EO and EC.

Conclusion

Results of this study indicate BW requires greater cardiovascular, metabolic, perceptual and neuromuscular demands than FW, which may cause postural instability particularly to those with compromised balance. While there are benefits to BW in rehabilitation settings, these factors should be considered when prescribing BW for training and/or rehabilitation exercise program (Duffell et al. [2], Warnica et al. [3]).

from #Audiology via ola Kala on Inoreader https://ift.tt/2z9Lq40
via IFTTT

Effect of force magnitude of touch on the components of postural sway

Publication date: September 2018

Source: Gait & Posture, Volume 65

Author(s): Janina Manzieri Prado-Rico, Sandra Regina Alouche, Ariani Cardoso Sodré, Rafaela Barroso de Souza Costa Garbus, Sandra Maria Sbeghen Ferreira de Freitas

Abstract

Background

Lightly touching the tip of the index finger on an external surface reduces the postural sway during upright standing due to the additional somatosensory information provided by the touch to the postural control system. But when the individuals apply more force, it provides more mechanical support. However, because most of the studies investigated only two levels of force, whether the control mechanisms of postural sway are affected by the different force levels was unknown.

Research question

To examine the influence of the magnitude of force (up to 1, 2, 4, 6 or 8 N) applied to the touch bar on the mechanisms used to control the postural sway during quiet standing with eyes open or closed.

Methods

Ten young right-handed adults stood for 35 s on a force platform, with feet apart, while touched a rigid bar with different force levels with eyes open or closed. The amplitude and velocity of the center of pressure and its components, Rambling and Trembling trajectories, respectively, related to more supraspinal and spinal control mechanisms, were assessed.

Results

The touch reduced all trajectories, mainly of the Rambling component and with closed eyes. There was a floor effect of the touch force as amplitudes and velocities were minimal at 4 N of force.

Significance

The component of postural sway under the supraspinal neural control is more affected by different force magnitudes applied to the touch bar.

from #Audiology via ola Kala on Inoreader https://ift.tt/2lS9P4q
via IFTTT

Walking combined with reach-to-grasp while crossing obstacles at different distances

Publication date: September 2018

Source: Gait & Posture, Volume 65

Author(s): Natalia Madalena Rinaldi, Jongil Lim, Joseph Hamill, Richard Van Emmerik, Renato Moraes

Abstract

Background

Obstacle avoidance and object prehension occur regularly in real-world environments (walking up/down steps and opening a door). However, it is not known how walking and prehension change when there is an increase in the level of difficulty of the walking task.

Research question

We investigated the changes in walking and reach-tograsp when performing these two motor skills concomitantly in the presence of an obstacle on the ground positioned in different locations in relation to the object-to-be-grasped.

Methods

Fifteen young adults walked and grasped a dowel placed on a support with the obstacle positioned at the step before (N-1), during (N) and after (N + 1) the prehension task.

Results

The prehension task did not affect leading limb obstacle negotiation. Toe clearance and maximum toe elevation were lesser at obstacle position N + 1 than at obstacle position N-1 when combining grasping and obstacle-crossing task for the trailing limb. Step width increased in the presence of the obstacle-crossing task independent of obstacle location. The correlation between foot position before the obstacle and toe clearance revealed that the addition of the prehension task disrupted the relationship between these variables for the trailing limb. Foot placement and limb elevation were unaffected by the prehension task. The reaching component was unaffected by the increased level of difficulty of the walking task. The grasping component was affected by the increased level of difficulty of the walking task, as the time to peak grip aperture occurred earlier in the presence of the obstacle at position N, and may indicate a cautious strategy to grasp the dowel successfully.

Significance

Our results showed that prospective control is affected after the prehension since the attention to grasping may have impaired the acquisition of visual information for planning the trailing limb elevation.

from #Audiology via ola Kala on Inoreader https://ift.tt/2zdMP9x
via IFTTT

Carrying asymmetric loads while walking on an uneven surface

Publication date: September 2018

Source: Gait & Posture, Volume 65

Author(s): Junsig Wang, Jason C. Gillette

Abstract

Background

Individuals often carry asymmetric loads over challenging surfaces such as uneven or irregular terrain, which may require a higher demand for postural control than walking on an even surface.

Research Question

The purpose of this study was to assess postural stability in the medial-lateral (ML) direction while carrying unilateral versus bilateral loads when walking on even versus uneven surfaces.

Methods

Nineteen healthy young adults walked on even and uneven surface treadmills under three load conditions: no load, 20% body weight (BW) bilateral load, and 20% BW unilateral load. A Pedar in-shoe pressure system (Novel, Munich, Germany) was used to evaluate center of pressure (COP)-based parameters.

Results

Carrying 20% BW bilateral or unilateral loads significantly increased double support ratio. In addition, carrying a 20% BW unilateral load significantly increased coefficient of variation (CV) of double support ratio, CV of ML COP excursion, and CV of ML COP velocity. Walking on an uneven surface significantly increased double support ratio, ML COP excursion, ML COP velocity, and CV of double support ratio. When carrying a 20% BW unilateral load, unloaded limb stance had significantly increased double support ratio and ML COP velocity, although it appears that the loaded limb may be used to make step-by-step adjustments as evidenced by the higher CV of ML COP velocity.

Significance

Unilateral load carriage, walking on uneven surfaces, and unloaded leg stance are of particular concern when considering postural stability.

from #Audiology via ola Kala on Inoreader https://ift.tt/2lVoUSH
via IFTTT

Fear of falling, not falls, impacts leisure-time physical activity in people with multiple sclerosis

Publication date: September 2018

Source: Gait & Posture, Volume 65

Author(s): Alon Kalron, Roy Aloni, Uri Givon, Shay Menascu

Abstract

Background

There is a consensus that physical activity is imperative for people with MS (PwMS). However, regardless of the benefits, many PwMS do not participate in any meaningful physical activity.

Aim

To examine the relationship between leisure-time physical activity with clinical characteristics and common symptoms in PwMS.

Methods

The sample included 190 PwMS (107 women), mean age 40.8 (S.D = 13.1) and mean disease duration of 6.4 (SD = 8.3) years since diagnosis. Outcome measures included the Godin Leisure-Time Exercise Questionnaire (GLTEQ), Four Square Step Test (FSST), 2-Minute Walk test (2 mWT), Timed Up and Go test (TUG), Timed 25-Foot Walk test (T25FW), fall status, Falls Efficacy Scale International (FES-I), Modified Fatigue Impact Scale (MFIS), walking speed and the Multiple Sclerosis Walking Scale self-reported questionnaire (MSWS-12).

Results

Eighty-six PwMS were classified as active (GLTEQ = 31.6 (S.D = 16.7); 104 were insufficiently active (GLTEQ = 3.0 (S.D = 4.3). Insufficiently active PwMS demonstrated a slower walking speed, elevated fatigue, more concerns of falling and additional walking difficulties compared to active PwMS. Non-significant differences between groups were observed in the TUG, 2 mWT, FSST, T25FWT and fall status. According to the linear regression, by utilizing the FES-I we observed a 12.2% variance related to leisure-time physical activity. The independent variables: EDSS, MSWS-12, fatigue and walking speed were non-significant.

Significance

The present findings highlight the impact of concern of falling on physical activity in PwMS. This knowledge may represent an opportunity to improve care and enhance physical activity in the MS population.

from #Audiology via ola Kala on Inoreader https://ift.tt/2zjG8mC
via IFTTT

P 020 - Is gait asymmetry correlated to anatomic leg length discrepancy when abnormal clinical findings are also present?

Publication date: Available online 4 July 2018

Source: Gait & Posture

Author(s): S. Khamis, B. Danino, E. Carmeli

from #Audiology via ola Kala on Inoreader https://ift.tt/2lUe5QT
via IFTTT

O 074 - The impact of dynamic simulation on diabetic foot prevention: two different approaches combining gait analysis and finite element modelling

Publication date: Available online 4 July 2018

Source: Gait & Posture

Author(s): A. Guiotto, F. Bellè, G. Rao, A. Jacques, Z. Sawacha

from #Audiology via ola Kala on Inoreader https://ift.tt/2z9LbWE
via IFTTT

P 030 - Personalized vs Average normal patterns to identify pathological motion

Publication date: Available online 4 July 2018

Source: Gait & Posture

Author(s): J.M. Baydal-Bertomeu, E. Medina-Ripoll, M.F. Peydro, J.F. Pedrero, J. López-Pascual

from #Audiology via ola Kala on Inoreader https://ift.tt/2lUe4fN
via IFTTT

P 054 - Evaluation of ground reaction forces by inverse dynamics analysis

Publication date: Available online 4 July 2018

Source: Gait & Posture

Author(s): R. Van Hulle, C. Schwartz, V. Denoël, J.L. Croisier, B. Forthomme, O. Brüls

from #Audiology via ola Kala on Inoreader https://ift.tt/2u6XywV
via IFTTT

P 037 - Prediction of moments from movements without force platforms using artificial neural networks a pilot test

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): P. Osateerakun, G. Barton, R. Foster, S. Bennett, R. Lakshminarayan

from #Audiology via ola Kala on Inoreader https://ift.tt/2lUe0wz
via IFTTT

P 061 – Determination of biomechanical influences of increased femoral anteversion (twisted leg) on running for developing individual

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): A. Apti, N.E. Akalan, S. Kuchimov, Y. Temelli, Ö.İ. Kılıçoğlu, A. Kurt, F. Miller

from #Audiology via ola Kala on Inoreader https://ift.tt/2u6riKg
via IFTTT

P 036 - Pressure mapping analysis for forward and backward gait

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): A. Mosiołek, A. Hadamus, M. Selegrat, M. Wąsak, S. Wójtowicz, Z. Wroński, K. Wiśniewska, M. Grabowicz, A. Bugalska, D. Białoszewski

from #Audiology via ola Kala on Inoreader https://ift.tt/2lV48Tt
via IFTTT

O 104 - MRI-based musculoskeletal models for the quantification of gait in children with Juvenile Idiopathic Arthritis

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): E. Montefiori, L. Modenese, R. Di Marco, S. Magni-Manzoni, C. Malattia, M. Petrarca, A. Ronchetti, P. van Dijkhuizen, M. Viceconti, C. Mazzà

from #Audiology via ola Kala on Inoreader https://ift.tt/2u6xpOv
via IFTTT

P 043 - Center of Pressure Progression and Ground Reaction Forces Are Altered in Cerebral Palsy Crouch Gait

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): A. Salehi, A. Khandan, M. Arab Baniasad, S. Baghdadi, F. Farahmand, H. Zohoor

from #Audiology via ola Kala on Inoreader https://ift.tt/2lURS5i
via IFTTT

O 102 - How does load transfer with weight reduction in obese children: A 3-year follow-up study

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): L. Yang, R. Li, H. Fan

from #Audiology via ola Kala on Inoreader https://ift.tt/2z9L7WU
via IFTTT

P 025 - Lower limb muscles activity during imagination of gait

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): B. Kolářová, M. Tomsa, J. Richards, P. Kolář, O. Hana

from #Audiology via ola Kala on Inoreader https://ift.tt/2lURROM
via IFTTT

P 042 - Gait complexity quantified using inertial measurement units in children with cerebral palsy

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): H. Piitulainen, T. Rantalainen, J.P. Kulmala, H. Mäenpää

from #Audiology via ola Kala on Inoreader https://ift.tt/2zfwYr6
via IFTTT

P 031 - Kinematics of Lateral Step Down is the best discriminator of women with patellofemoral pain

Publication date: Available online 3 July 2018

Source: Gait & Posture

Author(s): Ferreira C., Barton G., Delgado L., Rabelo N., Politti F., Lucareli P.

from #Audiology via ola Kala on Inoreader https://ift.tt/2lWY9xa
via IFTTT

Neural representation of interaural correlation in human auditory brainstem: Comparisons between temporal-fine structure and envelope

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Qian Wang, Hao Lu, Zhemeng Wu, Liang Li

Abstract

Central processing of interaural correlation (IAC), which depends on the precise representation of acoustic signals from the two ears, is essential for both localization and recognition of auditory objects. A complex soundwave is initially filtered by the peripheral auditory system into multiple narrowband waves, which are further decomposed into two functionally distinctive components: the quickly-varying temporal-fine structure (TFS) and the slowly-varying envelope. In rats, a narrowband noise can evoke auditory-midbrain frequency-following responses (FFRs) that contain both the TFS component (FFR_TFS) and the envelope component (FFR_Env), which represent the TFS and envelope of the narrowband noise, respectively. These two components are different in sensitivity to the interaural time disparity. In human listeners, the present study investigated whether the FFR_TFS and FFR_Env components of brainstem FFRs to a narrowband noise are different in sensitivity to IAC and whether there are potential brainstem mechanisms underlying the integration of the two components. The results showed that although both the amplitude of FFR_TFS and that of FFR_Env were significantly affected by shifts of IAC between 1 and 0, the stimulus-to-response correlation for FFR_TFS, but not that for FFR_Env, was sensitive to the IAC shifts. Moreover, in addition to the correlation between the binaurally evoked FFR_TFS and FFR_Env, the correlation between the IAC-shift-induced change of FFR_TFS and that of FFR_Env was significant. Thus, the TFS information is more precisely represented in the human auditory brainstem than the envelope information, and the correlation between FFR_TFS and FFR_Env for the same narrowband noise suggest a brainstem binding mechanism underlying the perceptual integration of the TFS and envelope signals.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KAt3ub
via IFTTT

Intracochlear pressure measurements during acoustic shock wave exposure

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Nathaniel T. Greene, Mohamed A. Alhussaini, James R. Easter, Theodore F. Argo, Tim Walilko, Daniel J. Tollin

Abstract

Introduction

Injuries to the peripheral auditory system are among the most common results of high intensity impulsive acoustic exposure. Prior studies of high intensity sound transmission by the ossicular chain have relied upon measurements in animal models, measurements at more moderate sound levels (i.e. < 130 dB SPL), and/or measured responses to steady-state noise. Here, we directly measure intracochlear pressure in human cadaveric temporal bones, with fiber optic pressure sensors placed in scala vestibuli (SV) and tympani (ST), during exposure to shock waves with peak positive pressures between ∼7 and 83 kPa.

Methods

Eight full-cephalic human cadaver heads were exposed, face-on, to acoustic shock waves in a 45 cm diameter shock tube. Specimens were exposed to impulses with nominal peak overpressures of 7, 28, 55, & 83 kPa (171, 183, 189, & 192 dB pSPL), measured in the free field adjacent to the forehead. Specimens were prepared bilaterally by mastoidectomy and extended facial recess to expose the ossicular chain. Ear canal (EAC), middle ear, and intracochlear sound pressure levels were measured with fiber-optic pressure sensors. Surface-mounted sensors measured SPL and skull strain near the opening of each EAC and at the forehead.

Results

Measurements on the forehead showed incident peak pressures approximately twice that measured by adjacent free-field and EAC entrance sensors, as expected based on the sensor orientation (normal vs tangential to the shock wave propagation). At 7 kPa, EAC pressure showed gain, calculated from the frequency spectra, consistent with the ear canal resonance, and gain in the intracochlear pressures (normalized to the EAC pressure) were consistent with (though somewhat lower than) previously reported middle ear transfer functions. Responses to higher intensity impulses tended to show lower intracochlear gain relative to EAC, suggesting sound transmission efficiency along the ossicular chain is reduced at high intensities. Tympanic membrane (TM) rupture was observed following nearly every exposure 55 kPa or higher.

Conclusions

Intracochlear pressures reveal lower middle-ear transfer function magnitudes (i.e. reduced gain relative to the ear canal) for high sound pressure levels, thus revealing lower than expected cochlear exposure based on extrapolation from cochlear pressures measured at more moderate sound levels. These results are consistent with lowered transmissivity of the ossicular chain at high intensities, and are consistent with our prior report measuring middle ear transfer functions in human cadaveric temporal bones with high intensity tone pips.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MPznKR
via IFTTT

Investigation of the 2f1−f2 and 2f2−f1 distortion product otoacoustic emissions using a computational model of the gerbil ear

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Haiqi Wen, Thomas Bowling, Julien Meaud

Abstract

In this work, a three-dimensional computational model of the gerbil ear is used to investigate the generation of the 2f1−f2 and 2f2−f1 distortion product otoacoustic emissions (DPOAEs). In order to predict both the distortion and reflection sources, cochlear roughness is modeled by introducing random inhomogeneities in the outer hair cell properties. The model was used to simulate the generation of DPOAEs in response to a two-tone stimulus for various primary stimulus levels and frequency ratios. As in published experiments, the 2f1−f2 DPOAEs are mostly dominated by the distortion component while the 2f2−f1 DPOAEs are dominated by the reflection component; furthermore, the influence of the levels and frequency ratio of the primaries are consistent with measurements. Analysis of the intracochlear response shows that the distortion component has the highest magnitude at all longitudinal locations for the 2f1−f2 distortion product (DP) while the distortion component only dominates close to the DP best place in the case of the 2f2−f1 DP. Decomposition of the intracochlear DPs into forward and reverse waves demonstrates that the 2f1−f2 DP generates reverse waves for both the distortion and reflection components; however, a reverse wave is only generated for the reflection component in the case of the 2f2−f1 DP. As in experiments in the gerbil, the group delay of the reflection component of the DPOAE is between 1× and 2× the forward group delay, which is consistent with the propagation of DP towards the stapes as slow reverse waves.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KOv45o
via IFTTT

Differential fates of tissue macrophages in the cochlea during postnatal development

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Youyi Dong, Celia Zhang, Mitchell Frye, Weiping Yang, Dalian Ding, Ashu Sharma, Weiwei Guo, Bo Hua Hu

Abstract

The cochlea contains macrophages. These cells participate in inflammatory responses to cochlear pathogenesis. However, it is not clear how and when these cells populate the cochlea during postnatal development. The current study aims to determine the postnatal development of cochlear macrophages with the focus on macrophage development in the organ of Corti and the basilar membrane. Cochleae were collected from C57BL/6J mice at ages of postnatal day (P) 1 to P21, as well as from mature mice (1–4 months). Macrophages were identified based on their expression of F4/80 and Iba1, as well as their unique morphologies. Two sets of macrophages were identified in the regions of the organ of Corti and the basilar membrane. One set resides on the scala tympani side of the basilar membrane. These cells have a round shape at P1 and start to undergo site-specific differentiation at P4. Apical macrophages adopt a dendritic shape. Middle and basal macrophages take on an irregular shape with short projections. Basal macrophages further differentiate into an amoeboid shape. The other set of macrophages resides above the basilar membrane, either beneath the cells of the organ of Corti or along the spiral vessel of the basilar membrane. As the sensory epithelium matures, these cells undergo developmental death with the phenotypes of apoptosis. Macrophages are also identified in the spiral ligament, spiral limbus, and neural regions. Their numbers decrease during postnatal development. Together, these results suggest a dynamic rearrangement of the macrophage population during postnatal cochlear development.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRPyHP
via IFTTT

Human medial efferent activity elicited by dynamic versus static contralateral noises

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Ian B. Mertes

Abstract

The medial olivocochlear reflex (MOCR) modifies cochlear amplifier function to improve encoding of signals in static noise, but conflicting results have been reported regarding how the MOCR responds to dynamic, temporally-complex noises. The current study utilized three MOCR elicitors with identical spectral content but different temporal properties: broadband noise, amplitude-modulated noise, and speech envelope-modulated noise. MOCR activity was assessed using contralateral inhibition of transient-evoked otoacoustic emissions in 27 normal-hearing young adults. Elicitors were presented contralaterally at two intensities of 50 and 60 dB SPL. Magnitude and growth of contralateral inhibition with increasing elicitor intensity were compared across the three elicitor types. Results revealed that contralateral inhibition was significantly larger at the elicitor intensity of 60 dB SPL than at 50 dB SPL, but there were no significant differences in the magnitude and growth of inhibition across the three elicitors, contrary to hypothesis. These results suggest that the MOCR responds similarly to both static and dynamic noise.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KMrXL6
via IFTTT

Impact of SNR, masker type and noise reduction processing on sentence recognition performance and listening effort as indicated by the pupil dilation response

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Barbara Ohlenforst, Dorothea Wendt, Sophia E. Kramer, Graham Naylor, Adriana A. Zekveld, Thomas Lunner

Abstract

Recent studies have shown that activating the noise reduction scheme in hearing aids results in a smaller peak pupil dilation (PPD), indicating reduced listening effort, at 50% and 95% correct sentence recognition with a 4-talker masker. The objective of this study was to measure the effect of the noise reduction scheme (on or off) on PPD and sentence recognition across a wide range of signal-to-noise ratios (SNRs) from +16 dB to −12 dB and two masker types (4-talker and stationary noise). Relatively low PPDs were observed at very low (−12 dB) and very high (+16 dB to +8 dB) SNRs presumably due to ‘giving up’ and ‘easy listening’, respectively. The maximum PPD was observed with SNRs at approximately 50% correct sentence recognition. Sentence recognition with both masker types was significantly improved by the noise reduction scheme, which corresponds to the shift in performance from SNR function at approximately 5 dB toward a lower SNR. This intelligibility effect was accompanied by a corresponding effect on the PPD, shifting the peak by approximately 4 dB toward a lower SNR. In addition, with the 4-talker masker, when the noise reduction scheme was active, the PPD was smaller overall than that when the scheme was inactive. We conclude that with the 4-talker masker, noise reduction scheme processing provides a listening effort benefit in addition to any effect associated with improved intelligibility. Thus, the effect of the noise reduction scheme on listening effort incorporates more than can be explained by intelligibility alone, emphasizing the potential importance of measuring listening effort in addition to traditional speech reception measures.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MNNJLY
via IFTTT

Increased spontaneous firing rates in auditory midbrain following noise exposure are specifically abolished by a Kv3 channel modulator

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Lucy A. Anderson, Lara L. Hesse, Nadia Pilati, Warren M.H. Bakay, Giuseppe Alvaro, Charles H. Large, David McAlpine, Roland Schaette, Jennifer F. Linden

Abstract

Noise exposure has been shown to produce long-lasting increases in spontaneous activity in central auditory structures in animal models, and similar pathologies are thought to contribute to clinical phenomena such as hyperacusis or tinnitus in humans. Here we demonstrate that multi-unit spontaneous neuronal activity in the inferior colliculus (IC) of mice is significantly elevated four weeks following noise exposure at recording sites with frequency tuning within or near the noise exposure band, and this selective central auditory pathology can be normalised through administration of a novel compound that modulates activity of Kv3 voltage-gated ion channels. The compound had no statistically significant effect on IC spontaneous activity without noise exposure, nor on thresholds or frequency tuning of tone-evoked responses either with or without noise exposure. Administration of the compound produced some reduction in the magnitude of evoked responses to a broadband noise, but unlike effects on spontaneous rates, these effects on evoked responses were not specific to recording sites with frequency tuning within the noise exposure band. Thus, the results suggest that modulators of Kv3 channels can selectively counteract increases in spontaneous activity in the auditory midbrain associated with noise exposure.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KL9z5q
via IFTTT

Spatial hearing ability of the pigmented Guinea pig (Cavia porcellus): Minimum audible angle and spatial release from masking in azimuth

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Nathaniel T. Greene, Kelsey L. Anbuhl, Alexander T. Ferber, Marisa DeGuzman, Paul D. Allen, Daniel J. Tollin

Abstract

Despite the common use of guinea pigs in investigations of the neural mechanisms of binaural and spatial hearing, their behavioral capabilities in spatial hearing tasks have surprisingly not been thoroughly investigated. To begin to fill this void, we tested the spatial hearing of adult male guinea pigs in several experiments using a paradigm based on the prepulse inhibition (PPI) of the acoustic startle response. In the first experiment, we presented continuous broadband noise from one speaker location and switched to a second speaker location (the “prepulse”) along the azimuth prior to presenting a brief, ∼110 dB SPL startle-eliciting stimulus. We found that the startle response amplitude was systematically reduced for larger changes in speaker swap angle (i.e., greater PPI), indicating that using the speaker “swap” paradigm is sufficient to assess stimulus detection of spatially separated sounds. In a second set of experiments, we swapped low- and high-pass noise across the midline to estimate their ability to utilize interaural time- and level-difference cues, respectively. The results reveal that guinea pigs can utilize both binaural cues to discriminate azimuthal sound sources. A third set of experiments examined spatial release from masking using a continuous broadband noise masker and a broadband chirp signal, both presented concurrently at various speaker locations. In general, animals displayed an increase in startle amplitude (i.e., lower PPI) when the masker was presented at speaker locations near that of the chirp signal, and reduced startle amplitudes (increased PPI) indicating lower detection thresholds when the noise was presented from more distant speaker locations. In summary, these results indicate that guinea pigs can: 1) discriminate changes in source location within a hemifield as well as across the midline, 2) discriminate sources of low- and high-pass sounds, demonstrating that they can effectively utilize both low-frequency interaural time and high-frequency level difference sound localization cues, and 3) utilize spatial release from masking to discriminate sound sources. This report confirms the guinea pig as a suitable spatial hearing model and reinforces prior estimates of guinea pig hearing ability from acoustical and physiological measurements.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRP58x
via IFTTT

Cortical processing of location changes in a “cocktail-party” situation: Spatial oddball effects on electrophysiological correlates of auditory selective attention

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Jörg Lewald, Michael-Christian Schlüter, Stephan Getzmann

Abstract

Neural mechanisms of selectively attending to a sound source of interest in a simulated “cocktail-party” situation, composed of multiple competing sources, were investigated using event-related potentials in combination with a spatial oddball design. Subjects either detected rare spatial deviants in a series of standard sounds or passively listened. Targets either appeared in isolation or in the presence of two distractor sound sources at different locations (“cocktail-party” condition). Deviant-minus-standard difference potentials revealed mismatch negativity, P3a, and P3b. However, mainly the P3b was modulated by spatial conditions of stimulation, with lower amplitude for “cocktail-party”, than single, sounds. In the active condition, cortical source localization revealed two distinct foci of maximum differences in electrical activity for the contrast of single vs. “cocktail-party” sounds: the right inferior frontal junction and the right anterior superior parietal lobule. These areas may be specifically involved in processes associated with selective attention in a “cocktail-party” situation.

Graphical abstract

from #Audiology via ola Kala on Inoreader https://ift.tt/2KLTs7r
via IFTTT

Effects of lifetime noise exposure on the middle-age human auditory brainstem response, tinnitus and speech-in-noise intelligibility

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Joaquin T. Valderrama, Elizabeth Francis Beach, Ingrid Yeend, Mridula Sharma, Bram Van Dun, Harvey Dillon

Abstract

Recent animal studies have shown that the synapses between inner hair cells and the dendrites of the spiral ganglion cells they innervate are the elements in the cochlea most vulnerable to excessive noise exposure. Particularly in rodents, several studies have concluded that exposure to high level octave-band noise for 2 h leads to an irreversible loss of around 50% of synaptic ribbons, leaving audiometric hearing thresholds unaltered. Cochlear synaptopathy following noise exposure is hypothesized to degrade the neural encoding of sounds at the subcortical level, which would help explain certain listening-in-noise difficulties reported by some subjects with otherwise ‘normal’ hearing. In response to this peripheral damage, increased gain of central stages of the auditory system has been observed across several species of mammals, particularly in association with tinnitus. The auditory brainstem response (ABR) wave I amplitude and waves I-V amplitude ratio have been suggested as non-invasive indicators of cochlear synaptopathy and central gain activation respectively, but the evidence for these hearing disorders in humans is inconclusive. In this study, we evaluated the influence of lifetime noise exposure (LNE) on the human ABR and on speech-in-noise intelligibility performance in a large cohort of adults aged 29 to 55. Despite large inter-subject variability, results showed a moderate, but statistically significant, negative correlation between the ABR wave I amplitude and LNE, consistent with cochlear synaptopathy. The results also showed (a) that central gain mechanisms observed in animal studies might also occur in humans, in which higher stages of the auditory pathway appear to compensate for reduced input from the cochlea; (b) that tinnitus was associated with activation of central gain mechanisms; (c) that relevant cognitive and subcortical factors influence speech-in-noise intelligibility, in particular, longer ABR waves I-V interpeak latencies were associated with poorer performance in understanding speech in noise when central gain mechanisms were active; and (d) absence of a significant relationship between LNE and tinnitus, central gain activation or speech-in-noise performance. Although this study supports the possible existence of cochlear synaptopathy in humans, the great degree of variability, the lack of uniformity in central gain activation and the significant involvement of attention in speech-in-noise performance suggests that noise-induced cochlear synaptopathy is, at most, one of several factors that play a role in humans' speech-in-noise performance.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MROR1b
via IFTTT

Effect of sound level on virtual and free-field localization of brief sounds in the anterior median plane

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Frederic Marmel, Miriam I. Marrufo-Pérez, Jan Heeren, Stephan Ewert, Enrique A. Lopez-Poveda

Abstract

The detection of high-frequency spectral notches has been shown to be worse at 70–80 dB sound pressure level (SPL) than at higher levels up to 100 dB SPL. The performance improvement at levels higher than 70–80 dB SPL has been related to an ‘ideal observer’ comparison of population auditory nerve spike trains to stimuli with and without high-frequency spectral notches. Insofar as vertical localization partly relies on information provided by pinna-based high-frequency spectral notches, we hypothesized that localization would be worse at 70–80 dB SPL than at higher levels. Results from a first experiment using a virtual localization set-up and non-individualized head-related transfer functions (HRTFs) were consistent with this hypothesis, but a second experiment using a free-field set-up showed that vertical localization deteriorates monotonically with increasing level up to 100 dB SPL. These results suggest that listeners use different cues when localizing sound sources in virtual and free-field conditions. In addition, they confirm that the worsening in vertical localization with increasing level continues beyond 70–80 dB SPL, the highest levels tested by previous studies. Further, they suggest that vertical localization, unlike high-frequency spectral notch detection, does not rely on an ‘ideal observer’ analysis of auditory nerve spike trains.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KLxdyM
via IFTTT

Estimation of the ear canal displacement field due to in-ear device insertion using a registration method on a human-like artificial ear

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): S. Benacchio, O. Doutres, A. Le Troter, A. Varoquaux, E. Wagnac, V. Callot, F. Sgard

Abstract

Passive and active in-ear devices (IED) occluding the ear canal are commonly used to (i) protect people from high noise levels (earplugs), (ii) assist people suffering from hearing impairment (hearing aids) or (iii) help people in listening from their sound systems (earbuds). However, the usability and/or efficiency of IEDs can be greatly affected by several discomfort components (physical, acoustical and functional). The mechanical pressure exerted by the IED onto the ear canal walls is greatly suspected to affect the aforementioned comfort components. This physical characteristic is closely related to the displacement field induced by the IED insertion, which has to be known for a better understanding of perceived discomfort. Thus, this paper proposes to validate a method based on medical images to estimate the displacement field of the ear canal walls due to the insertion of an IED. The approach is validated on a human-like artificial ear with canal geometry deformed using two custom molded IEDs with controlled shapes. These geometries are obtained using computed tomography imaging and the displacement field is computed using a registration method. The errors due to the ear canal segmentation and to the registration steps are small enough to compute a relevant estimation of the expected displacement field. Results show that the amplitude of the displacement and its location into the ear canal can be evaluated with an accuracy of ± 0.2 mm and ± 0.4 mm respectively. Preliminary results on images with a degraded resolution indicate that the proposed approach used to assess the displacement field of the ear canal walls using computed tomography images could be applied on magnetic resonance images, which is a preferred method to image human subject ear canals for future investigations.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MPylyv
via IFTTT

COMT and the neurogenetic architecture of hearing loss induced tinnitus

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Sven Vanneste, Ola Alsalman, Dirk De Ridder

Abstract

As the COMT polymorphism is especially prominent in the prefrontal cortex and has been associated with auditory gating, we hypothesize that tinnitus patients with this polymorphism have altered activity in the ventromedial prefrontal/anterior cingulate areas that modulates the tinnitus percept. To test this, we recruited a total of 40 tinnitus subjects and 20 healthy controls for an EEG study. A comparison between tinnitus subjects and healthy controls and their frequency of being Val/Val genotype or Met carriers (including Val/Met and Met/Met genotype) shows no significant effect, suggesting that the distributions for the tinnitus and healthy groups are similar. Our results show that an interaction between the amount of hearing loss and the COMT Val¹⁵⁸Met polymorphism can increase susceptibility to the clinical manifestation of tinnitus. We further demonstrate that the parahippocampus becomes involved in tinnitus in patients with hearing loss that are Met carriers. In these patients, the parahippocampus sends more tinnitus information to the pregenual anterior cingulate cortex and auditory cortex that is specifically related with increased loudness. At the same time, the pregenual anterior cingulate cortex, which normally functions as a gatekeeper, is not cancelling this auditory information, ultimately leading to increased tinnitus loudness.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KBiJlJ
via IFTTT

Editorial Board

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s):

from #Audiology via ola Kala on Inoreader https://ift.tt/2ML8JCQ
via IFTTT

Eardrum and columella displacement in single ossicle ears under quasi-static pressure variations

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Raf Claes, Pieter G.G. Muyshondt, Frederic Van Assche, Luc Van Hoorebeke, Peter Aerts, Joris J.J. Dirckx

Abstract

Although most birds encounter large pressure variations during flight, motion of the middle ear components as a result of changing ambient pressure are not well known or described. In the present study, motion of the columella footplate and tympanic membrane (extrastapedius) in domestic chickens (Gallus gallus domesticus) under quasi-static pressure conditions are provided. Micro-CT scans were made of cadaveric heads of chickens under positive (0.25 kPa, 0.5 kPa, 1 kPa, and 1.5 kPa) and negative (−0.25 kPa, −0.5 kPa, −1 kPa, and −1.5 kPa) middle ear pressure. Both extrastapedius and columella footplate displacements show a non-linear S-shaped curve as a function of pressure indicating non-linear response characteristics of the middle ear components. The S-curve is also seen in mammals, but unlike in mammals, the lateral piston-like displacement of both the columella footplate and extrastapedius, which is caused by an increased middle ear pressure are smaller than the medial piston-like displacements, caused by a decreased middle ear pressure of the same magnitude. Columella footplate piston displacements are always smaller than the extrastapedius piston displacements, indicating the flexibility of the extracolumella. The cone-shape of the avian tympanic membrane with inverted apex in comparison to the mammalian tympanic membrane can cause the inverted shape of the pressure response curve.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KBFOor
via IFTTT

Input-output curves of low and high spontaneous auditory nerve fibers are exponential near threshold

Publication date: Available online 4 July 2018

Source: Hearing Research

Author(s): J. Wiebe Horst, JoAnn McGee, Edward J. Walsh

Abstract

Input-output (IO) properties of cochlear transduction are frequently determined by analyzing the average discharge rates of auditory nerve fibers (ANFs) in response to relatively long tonal stimulation. The ANFs in cats have spontaneous discharge rates (SRs) that are bimodally distributed, peaking at low (<0.5 spikes/s) and high (∼60 spikes/s) rates, and rate-level characteristics differ depending upon SR. In an effort to assess the instantaneous IO properties of ANFs having different SRs, static IO-curves were constructed from period histograms based on phase-locking of spikes to the stimulus waveform. These curves provide information unavailable in conventional average rate-level curves. We find that all IO curves follow an exponential trajectory. It is argued that the exponential behavior represents the transduction in the IHC and that the difference among ANFs having different SRs is predominantly a difference in gain attributed most likely to synaptic drive. © 2018 The authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRziXk
via IFTTT

Perception of noise-vocoded tone complexes: A time domain analysis based on an auditory filterbank model

Publication date: Available online 4 July 2018

Source: Hearing Research

Author(s): William P. Shofner, Hayley Morris, Mackenzie Mills

Abstract

When a wideband harmonic tone complex (wHTC) is passed through a noise vocoder, the resulting sounds can have spectra with large peak-to-valley ratios, but little or no periodicity strength in the autocorrelation functions. We measured judgments of pitch strength for normal-hearing listeners for noise-vocoded wideband harmonic tone complexes (NV-wHTCs) relative to standard and anchor stimuli. The standard was a 1-channel NV-wHTC and the anchor was either the unprocessed wHTC or an infinitely-iterated rippled noise (IIRN). Although there is variability among individuals, the magnitude judgment functions obtained with the IIRN anchor suggest different listening strategies among individuals. In order to gain some insight into possible listening strategies, test stimuli were analyzed at the output of an auditory filterbank model based on gammatone filters. The weak periodicity strengths of NV-wHTCs observed in the stimulus autocorrelation functions are augmented at the output of the gammatone filterbank model. Six analytical models of pitch strength were evaluated based on summary correlograms obtained from the gammatone tone filterbank. The results of the filterbank analysis suggest that, contrary to the weak or absent periodicity strengths in the stimulus domain, temporal cues contribute to pitch strength perception of noise-vocoded harmonic stimuli such that listeners' judgments of pitch strength reflect a nonlinear, weighted average of the temporal information between the fine structure and the envelope.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KKGvel
via IFTTT

Development of electrophysiological and behavioural measures of electrode discrimination in adult cochlear implant users

Publication date: Available online 4 July 2018

Source: Hearing Research

Author(s): Rajeev Mathew, Deborah Vickers, Patrick Boyle, Azhar Shaida, David Selvadurai, Dan Jiang, Jaime Undurraga

Abstract

The plasticity of the auditory system enables it to adjust to electrical stimulation from cochlear implants (CI). Whilst speech perception may develop for many years after implant activation, very little is known about the changes in auditory processing that underpin these improvements. Such an understanding could help guide interventions that improve hearing performance. In this longitudinal study, we examine how electrode discrimination ability changes over time in newly implanted adult CI users. Electrode discrimination was measured with a behavioural task as well as the spatial auditory change complex (ACC), which is a cortical response to a change in place of stimulation. We show that there was significant improvement in electrode discrimination ability over time, though in certain individuals the process of accommodation was slower and more limited. We found a strong relationship between objective and behavioural measures of electrode discrimination using pass-fail rules. In several cases, the development of the spatial ACC preceded accurate behavioural discrimination. These data provide evidence for plasticity of auditory processing in adult CI users. Behavioural electrode discrimination score but not spatial ACC amplitude was found to be a significant predictor of speech perception. We suggest that it would be beneficial to measure electrode discrimination in CI users and that interventions that exploit the plastic capacity of the auditory system to improve basic auditory processing, could be used to optimize performance in CI users.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRVNv7
via IFTTT

Editorial Board

Publication date: July 2018

Source: Hearing Research, Volume 364

Author(s):

from #Audiology via ola Kala on Inoreader https://ift.tt/2KBFmGL
via IFTTT

The effects of the activation of the inner-hair-cell basolateral K+ channels on auditory nerve responses

Publication date: July 2018

Source: Hearing Research, Volume 364

Author(s): Alessandro Altoè, Ville Pulkki, Sarah Verhulst

Abstract

The basolateral membrane of the mammalian inner hair cell (IHC) expresses large voltage and Ca²⁺ gated outward K⁺ currents. To quantify how the voltage-dependent activation of the K⁺ channels affects the functionality of the auditory nerve innervating the IHC, this study adopts a model of mechanical-to-neural transduction in which the basolateral K⁺ conductances of the IHC can be made voltage-dependent or not. The model shows that the voltage-dependent activation of the K⁺ channels (i) enhances the phase-locking properties of the auditory fiber (AF) responses; (ii) enables the auditory nerve to encode a large dynamic range of sound levels; (iii) enables the AF responses to synchronize precisely with the envelope of amplitude modulated stimuli; and (iv), is responsible for the steep offset responses of the AFs. These results suggest that the basolateral K⁺ channels play a major role in determining the well-known response properties of the AFs and challenge the classical view that describes the IHC membrane as an electrical low-pass filter. In contrast to previous models of the IHC-AF complex, this study ascribes many of the AF response properties to fairly basic mechanisms in the IHC membrane rather than to complex mechanisms in the synapse.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MNQahG
via IFTTT

Neural representation of interaural correlation in human auditory brainstem: Comparisons between temporal-fine structure and envelope

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Qian Wang, Hao Lu, Zhemeng Wu, Liang Li

Abstract

Central processing of interaural correlation (IAC), which depends on the precise representation of acoustic signals from the two ears, is essential for both localization and recognition of auditory objects. A complex soundwave is initially filtered by the peripheral auditory system into multiple narrowband waves, which are further decomposed into two functionally distinctive components: the quickly-varying temporal-fine structure (TFS) and the slowly-varying envelope. In rats, a narrowband noise can evoke auditory-midbrain frequency-following responses (FFRs) that contain both the TFS component (FFR_TFS) and the envelope component (FFR_Env), which represent the TFS and envelope of the narrowband noise, respectively. These two components are different in sensitivity to the interaural time disparity. In human listeners, the present study investigated whether the FFR_TFS and FFR_Env components of brainstem FFRs to a narrowband noise are different in sensitivity to IAC and whether there are potential brainstem mechanisms underlying the integration of the two components. The results showed that although both the amplitude of FFR_TFS and that of FFR_Env were significantly affected by shifts of IAC between 1 and 0, the stimulus-to-response correlation for FFR_TFS, but not that for FFR_Env, was sensitive to the IAC shifts. Moreover, in addition to the correlation between the binaurally evoked FFR_TFS and FFR_Env, the correlation between the IAC-shift-induced change of FFR_TFS and that of FFR_Env was significant. Thus, the TFS information is more precisely represented in the human auditory brainstem than the envelope information, and the correlation between FFR_TFS and FFR_Env for the same narrowband noise suggest a brainstem binding mechanism underlying the perceptual integration of the TFS and envelope signals.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KAt3ub
via IFTTT

Intracochlear pressure measurements during acoustic shock wave exposure

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Nathaniel T. Greene, Mohamed A. Alhussaini, James R. Easter, Theodore F. Argo, Tim Walilko, Daniel J. Tollin

Abstract

Introduction

Injuries to the peripheral auditory system are among the most common results of high intensity impulsive acoustic exposure. Prior studies of high intensity sound transmission by the ossicular chain have relied upon measurements in animal models, measurements at more moderate sound levels (i.e. < 130 dB SPL), and/or measured responses to steady-state noise. Here, we directly measure intracochlear pressure in human cadaveric temporal bones, with fiber optic pressure sensors placed in scala vestibuli (SV) and tympani (ST), during exposure to shock waves with peak positive pressures between ∼7 and 83 kPa.

Methods

Eight full-cephalic human cadaver heads were exposed, face-on, to acoustic shock waves in a 45 cm diameter shock tube. Specimens were exposed to impulses with nominal peak overpressures of 7, 28, 55, & 83 kPa (171, 183, 189, & 192 dB pSPL), measured in the free field adjacent to the forehead. Specimens were prepared bilaterally by mastoidectomy and extended facial recess to expose the ossicular chain. Ear canal (EAC), middle ear, and intracochlear sound pressure levels were measured with fiber-optic pressure sensors. Surface-mounted sensors measured SPL and skull strain near the opening of each EAC and at the forehead.

Results

Measurements on the forehead showed incident peak pressures approximately twice that measured by adjacent free-field and EAC entrance sensors, as expected based on the sensor orientation (normal vs tangential to the shock wave propagation). At 7 kPa, EAC pressure showed gain, calculated from the frequency spectra, consistent with the ear canal resonance, and gain in the intracochlear pressures (normalized to the EAC pressure) were consistent with (though somewhat lower than) previously reported middle ear transfer functions. Responses to higher intensity impulses tended to show lower intracochlear gain relative to EAC, suggesting sound transmission efficiency along the ossicular chain is reduced at high intensities. Tympanic membrane (TM) rupture was observed following nearly every exposure 55 kPa or higher.

Conclusions

Intracochlear pressures reveal lower middle-ear transfer function magnitudes (i.e. reduced gain relative to the ear canal) for high sound pressure levels, thus revealing lower than expected cochlear exposure based on extrapolation from cochlear pressures measured at more moderate sound levels. These results are consistent with lowered transmissivity of the ossicular chain at high intensities, and are consistent with our prior report measuring middle ear transfer functions in human cadaveric temporal bones with high intensity tone pips.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MPznKR
via IFTTT

Investigation of the 2f1−f2 and 2f2−f1 distortion product otoacoustic emissions using a computational model of the gerbil ear

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Haiqi Wen, Thomas Bowling, Julien Meaud

Abstract

In this work, a three-dimensional computational model of the gerbil ear is used to investigate the generation of the 2f1−f2 and 2f2−f1 distortion product otoacoustic emissions (DPOAEs). In order to predict both the distortion and reflection sources, cochlear roughness is modeled by introducing random inhomogeneities in the outer hair cell properties. The model was used to simulate the generation of DPOAEs in response to a two-tone stimulus for various primary stimulus levels and frequency ratios. As in published experiments, the 2f1−f2 DPOAEs are mostly dominated by the distortion component while the 2f2−f1 DPOAEs are dominated by the reflection component; furthermore, the influence of the levels and frequency ratio of the primaries are consistent with measurements. Analysis of the intracochlear response shows that the distortion component has the highest magnitude at all longitudinal locations for the 2f1−f2 distortion product (DP) while the distortion component only dominates close to the DP best place in the case of the 2f2−f1 DP. Decomposition of the intracochlear DPs into forward and reverse waves demonstrates that the 2f1−f2 DP generates reverse waves for both the distortion and reflection components; however, a reverse wave is only generated for the reflection component in the case of the 2f2−f1 DP. As in experiments in the gerbil, the group delay of the reflection component of the DPOAE is between 1× and 2× the forward group delay, which is consistent with the propagation of DP towards the stapes as slow reverse waves.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KOv45o
via IFTTT

Differential fates of tissue macrophages in the cochlea during postnatal development

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Youyi Dong, Celia Zhang, Mitchell Frye, Weiping Yang, Dalian Ding, Ashu Sharma, Weiwei Guo, Bo Hua Hu

Abstract

The cochlea contains macrophages. These cells participate in inflammatory responses to cochlear pathogenesis. However, it is not clear how and when these cells populate the cochlea during postnatal development. The current study aims to determine the postnatal development of cochlear macrophages with the focus on macrophage development in the organ of Corti and the basilar membrane. Cochleae were collected from C57BL/6J mice at ages of postnatal day (P) 1 to P21, as well as from mature mice (1–4 months). Macrophages were identified based on their expression of F4/80 and Iba1, as well as their unique morphologies. Two sets of macrophages were identified in the regions of the organ of Corti and the basilar membrane. One set resides on the scala tympani side of the basilar membrane. These cells have a round shape at P1 and start to undergo site-specific differentiation at P4. Apical macrophages adopt a dendritic shape. Middle and basal macrophages take on an irregular shape with short projections. Basal macrophages further differentiate into an amoeboid shape. The other set of macrophages resides above the basilar membrane, either beneath the cells of the organ of Corti or along the spiral vessel of the basilar membrane. As the sensory epithelium matures, these cells undergo developmental death with the phenotypes of apoptosis. Macrophages are also identified in the spiral ligament, spiral limbus, and neural regions. Their numbers decrease during postnatal development. Together, these results suggest a dynamic rearrangement of the macrophage population during postnatal cochlear development.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRPyHP
via IFTTT

Human medial efferent activity elicited by dynamic versus static contralateral noises

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Ian B. Mertes

Abstract

The medial olivocochlear reflex (MOCR) modifies cochlear amplifier function to improve encoding of signals in static noise, but conflicting results have been reported regarding how the MOCR responds to dynamic, temporally-complex noises. The current study utilized three MOCR elicitors with identical spectral content but different temporal properties: broadband noise, amplitude-modulated noise, and speech envelope-modulated noise. MOCR activity was assessed using contralateral inhibition of transient-evoked otoacoustic emissions in 27 normal-hearing young adults. Elicitors were presented contralaterally at two intensities of 50 and 60 dB SPL. Magnitude and growth of contralateral inhibition with increasing elicitor intensity were compared across the three elicitor types. Results revealed that contralateral inhibition was significantly larger at the elicitor intensity of 60 dB SPL than at 50 dB SPL, but there were no significant differences in the magnitude and growth of inhibition across the three elicitors, contrary to hypothesis. These results suggest that the MOCR responds similarly to both static and dynamic noise.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KMrXL6
via IFTTT

Impact of SNR, masker type and noise reduction processing on sentence recognition performance and listening effort as indicated by the pupil dilation response

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Barbara Ohlenforst, Dorothea Wendt, Sophia E. Kramer, Graham Naylor, Adriana A. Zekveld, Thomas Lunner

Abstract

Recent studies have shown that activating the noise reduction scheme in hearing aids results in a smaller peak pupil dilation (PPD), indicating reduced listening effort, at 50% and 95% correct sentence recognition with a 4-talker masker. The objective of this study was to measure the effect of the noise reduction scheme (on or off) on PPD and sentence recognition across a wide range of signal-to-noise ratios (SNRs) from +16 dB to −12 dB and two masker types (4-talker and stationary noise). Relatively low PPDs were observed at very low (−12 dB) and very high (+16 dB to +8 dB) SNRs presumably due to ‘giving up’ and ‘easy listening’, respectively. The maximum PPD was observed with SNRs at approximately 50% correct sentence recognition. Sentence recognition with both masker types was significantly improved by the noise reduction scheme, which corresponds to the shift in performance from SNR function at approximately 5 dB toward a lower SNR. This intelligibility effect was accompanied by a corresponding effect on the PPD, shifting the peak by approximately 4 dB toward a lower SNR. In addition, with the 4-talker masker, when the noise reduction scheme was active, the PPD was smaller overall than that when the scheme was inactive. We conclude that with the 4-talker masker, noise reduction scheme processing provides a listening effort benefit in addition to any effect associated with improved intelligibility. Thus, the effect of the noise reduction scheme on listening effort incorporates more than can be explained by intelligibility alone, emphasizing the potential importance of measuring listening effort in addition to traditional speech reception measures.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MNNJLY
via IFTTT

Increased spontaneous firing rates in auditory midbrain following noise exposure are specifically abolished by a Kv3 channel modulator

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Lucy A. Anderson, Lara L. Hesse, Nadia Pilati, Warren M.H. Bakay, Giuseppe Alvaro, Charles H. Large, David McAlpine, Roland Schaette, Jennifer F. Linden

Abstract

Noise exposure has been shown to produce long-lasting increases in spontaneous activity in central auditory structures in animal models, and similar pathologies are thought to contribute to clinical phenomena such as hyperacusis or tinnitus in humans. Here we demonstrate that multi-unit spontaneous neuronal activity in the inferior colliculus (IC) of mice is significantly elevated four weeks following noise exposure at recording sites with frequency tuning within or near the noise exposure band, and this selective central auditory pathology can be normalised through administration of a novel compound that modulates activity of Kv3 voltage-gated ion channels. The compound had no statistically significant effect on IC spontaneous activity without noise exposure, nor on thresholds or frequency tuning of tone-evoked responses either with or without noise exposure. Administration of the compound produced some reduction in the magnitude of evoked responses to a broadband noise, but unlike effects on spontaneous rates, these effects on evoked responses were not specific to recording sites with frequency tuning within the noise exposure band. Thus, the results suggest that modulators of Kv3 channels can selectively counteract increases in spontaneous activity in the auditory midbrain associated with noise exposure.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KL9z5q
via IFTTT

Spatial hearing ability of the pigmented Guinea pig (Cavia porcellus): Minimum audible angle and spatial release from masking in azimuth

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Nathaniel T. Greene, Kelsey L. Anbuhl, Alexander T. Ferber, Marisa DeGuzman, Paul D. Allen, Daniel J. Tollin

Abstract

Despite the common use of guinea pigs in investigations of the neural mechanisms of binaural and spatial hearing, their behavioral capabilities in spatial hearing tasks have surprisingly not been thoroughly investigated. To begin to fill this void, we tested the spatial hearing of adult male guinea pigs in several experiments using a paradigm based on the prepulse inhibition (PPI) of the acoustic startle response. In the first experiment, we presented continuous broadband noise from one speaker location and switched to a second speaker location (the “prepulse”) along the azimuth prior to presenting a brief, ∼110 dB SPL startle-eliciting stimulus. We found that the startle response amplitude was systematically reduced for larger changes in speaker swap angle (i.e., greater PPI), indicating that using the speaker “swap” paradigm is sufficient to assess stimulus detection of spatially separated sounds. In a second set of experiments, we swapped low- and high-pass noise across the midline to estimate their ability to utilize interaural time- and level-difference cues, respectively. The results reveal that guinea pigs can utilize both binaural cues to discriminate azimuthal sound sources. A third set of experiments examined spatial release from masking using a continuous broadband noise masker and a broadband chirp signal, both presented concurrently at various speaker locations. In general, animals displayed an increase in startle amplitude (i.e., lower PPI) when the masker was presented at speaker locations near that of the chirp signal, and reduced startle amplitudes (increased PPI) indicating lower detection thresholds when the noise was presented from more distant speaker locations. In summary, these results indicate that guinea pigs can: 1) discriminate changes in source location within a hemifield as well as across the midline, 2) discriminate sources of low- and high-pass sounds, demonstrating that they can effectively utilize both low-frequency interaural time and high-frequency level difference sound localization cues, and 3) utilize spatial release from masking to discriminate sound sources. This report confirms the guinea pig as a suitable spatial hearing model and reinforces prior estimates of guinea pig hearing ability from acoustical and physiological measurements.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRP58x
via IFTTT

Cortical processing of location changes in a “cocktail-party” situation: Spatial oddball effects on electrophysiological correlates of auditory selective attention

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Jörg Lewald, Michael-Christian Schlüter, Stephan Getzmann

Abstract

Neural mechanisms of selectively attending to a sound source of interest in a simulated “cocktail-party” situation, composed of multiple competing sources, were investigated using event-related potentials in combination with a spatial oddball design. Subjects either detected rare spatial deviants in a series of standard sounds or passively listened. Targets either appeared in isolation or in the presence of two distractor sound sources at different locations (“cocktail-party” condition). Deviant-minus-standard difference potentials revealed mismatch negativity, P3a, and P3b. However, mainly the P3b was modulated by spatial conditions of stimulation, with lower amplitude for “cocktail-party”, than single, sounds. In the active condition, cortical source localization revealed two distinct foci of maximum differences in electrical activity for the contrast of single vs. “cocktail-party” sounds: the right inferior frontal junction and the right anterior superior parietal lobule. These areas may be specifically involved in processes associated with selective attention in a “cocktail-party” situation.

Graphical abstract

from #Audiology via ola Kala on Inoreader https://ift.tt/2KLTs7r
via IFTTT

Effects of lifetime noise exposure on the middle-age human auditory brainstem response, tinnitus and speech-in-noise intelligibility

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Joaquin T. Valderrama, Elizabeth Francis Beach, Ingrid Yeend, Mridula Sharma, Bram Van Dun, Harvey Dillon

Abstract

Recent animal studies have shown that the synapses between inner hair cells and the dendrites of the spiral ganglion cells they innervate are the elements in the cochlea most vulnerable to excessive noise exposure. Particularly in rodents, several studies have concluded that exposure to high level octave-band noise for 2 h leads to an irreversible loss of around 50% of synaptic ribbons, leaving audiometric hearing thresholds unaltered. Cochlear synaptopathy following noise exposure is hypothesized to degrade the neural encoding of sounds at the subcortical level, which would help explain certain listening-in-noise difficulties reported by some subjects with otherwise ‘normal’ hearing. In response to this peripheral damage, increased gain of central stages of the auditory system has been observed across several species of mammals, particularly in association with tinnitus. The auditory brainstem response (ABR) wave I amplitude and waves I-V amplitude ratio have been suggested as non-invasive indicators of cochlear synaptopathy and central gain activation respectively, but the evidence for these hearing disorders in humans is inconclusive. In this study, we evaluated the influence of lifetime noise exposure (LNE) on the human ABR and on speech-in-noise intelligibility performance in a large cohort of adults aged 29 to 55. Despite large inter-subject variability, results showed a moderate, but statistically significant, negative correlation between the ABR wave I amplitude and LNE, consistent with cochlear synaptopathy. The results also showed (a) that central gain mechanisms observed in animal studies might also occur in humans, in which higher stages of the auditory pathway appear to compensate for reduced input from the cochlea; (b) that tinnitus was associated with activation of central gain mechanisms; (c) that relevant cognitive and subcortical factors influence speech-in-noise intelligibility, in particular, longer ABR waves I-V interpeak latencies were associated with poorer performance in understanding speech in noise when central gain mechanisms were active; and (d) absence of a significant relationship between LNE and tinnitus, central gain activation or speech-in-noise performance. Although this study supports the possible existence of cochlear synaptopathy in humans, the great degree of variability, the lack of uniformity in central gain activation and the significant involvement of attention in speech-in-noise performance suggests that noise-induced cochlear synaptopathy is, at most, one of several factors that play a role in humans' speech-in-noise performance.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MROR1b
via IFTTT

Effect of sound level on virtual and free-field localization of brief sounds in the anterior median plane

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Frederic Marmel, Miriam I. Marrufo-Pérez, Jan Heeren, Stephan Ewert, Enrique A. Lopez-Poveda

Abstract

The detection of high-frequency spectral notches has been shown to be worse at 70–80 dB sound pressure level (SPL) than at higher levels up to 100 dB SPL. The performance improvement at levels higher than 70–80 dB SPL has been related to an ‘ideal observer’ comparison of population auditory nerve spike trains to stimuli with and without high-frequency spectral notches. Insofar as vertical localization partly relies on information provided by pinna-based high-frequency spectral notches, we hypothesized that localization would be worse at 70–80 dB SPL than at higher levels. Results from a first experiment using a virtual localization set-up and non-individualized head-related transfer functions (HRTFs) were consistent with this hypothesis, but a second experiment using a free-field set-up showed that vertical localization deteriorates monotonically with increasing level up to 100 dB SPL. These results suggest that listeners use different cues when localizing sound sources in virtual and free-field conditions. In addition, they confirm that the worsening in vertical localization with increasing level continues beyond 70–80 dB SPL, the highest levels tested by previous studies. Further, they suggest that vertical localization, unlike high-frequency spectral notch detection, does not rely on an ‘ideal observer’ analysis of auditory nerve spike trains.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KLxdyM
via IFTTT

Estimation of the ear canal displacement field due to in-ear device insertion using a registration method on a human-like artificial ear

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): S. Benacchio, O. Doutres, A. Le Troter, A. Varoquaux, E. Wagnac, V. Callot, F. Sgard

Abstract

Passive and active in-ear devices (IED) occluding the ear canal are commonly used to (i) protect people from high noise levels (earplugs), (ii) assist people suffering from hearing impairment (hearing aids) or (iii) help people in listening from their sound systems (earbuds). However, the usability and/or efficiency of IEDs can be greatly affected by several discomfort components (physical, acoustical and functional). The mechanical pressure exerted by the IED onto the ear canal walls is greatly suspected to affect the aforementioned comfort components. This physical characteristic is closely related to the displacement field induced by the IED insertion, which has to be known for a better understanding of perceived discomfort. Thus, this paper proposes to validate a method based on medical images to estimate the displacement field of the ear canal walls due to the insertion of an IED. The approach is validated on a human-like artificial ear with canal geometry deformed using two custom molded IEDs with controlled shapes. These geometries are obtained using computed tomography imaging and the displacement field is computed using a registration method. The errors due to the ear canal segmentation and to the registration steps are small enough to compute a relevant estimation of the expected displacement field. Results show that the amplitude of the displacement and its location into the ear canal can be evaluated with an accuracy of ± 0.2 mm and ± 0.4 mm respectively. Preliminary results on images with a degraded resolution indicate that the proposed approach used to assess the displacement field of the ear canal walls using computed tomography images could be applied on magnetic resonance images, which is a preferred method to image human subject ear canals for future investigations.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MPylyv
via IFTTT

COMT and the neurogenetic architecture of hearing loss induced tinnitus

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Sven Vanneste, Ola Alsalman, Dirk De Ridder

Abstract

As the COMT polymorphism is especially prominent in the prefrontal cortex and has been associated with auditory gating, we hypothesize that tinnitus patients with this polymorphism have altered activity in the ventromedial prefrontal/anterior cingulate areas that modulates the tinnitus percept. To test this, we recruited a total of 40 tinnitus subjects and 20 healthy controls for an EEG study. A comparison between tinnitus subjects and healthy controls and their frequency of being Val/Val genotype or Met carriers (including Val/Met and Met/Met genotype) shows no significant effect, suggesting that the distributions for the tinnitus and healthy groups are similar. Our results show that an interaction between the amount of hearing loss and the COMT Val¹⁵⁸Met polymorphism can increase susceptibility to the clinical manifestation of tinnitus. We further demonstrate that the parahippocampus becomes involved in tinnitus in patients with hearing loss that are Met carriers. In these patients, the parahippocampus sends more tinnitus information to the pregenual anterior cingulate cortex and auditory cortex that is specifically related with increased loudness. At the same time, the pregenual anterior cingulate cortex, which normally functions as a gatekeeper, is not cancelling this auditory information, ultimately leading to increased tinnitus loudness.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KBiJlJ
via IFTTT

Editorial Board

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s):

from #Audiology via ola Kala on Inoreader https://ift.tt/2ML8JCQ
via IFTTT

Eardrum and columella displacement in single ossicle ears under quasi-static pressure variations

Publication date: August 2018

Source: Hearing Research, Volume 365

Author(s): Raf Claes, Pieter G.G. Muyshondt, Frederic Van Assche, Luc Van Hoorebeke, Peter Aerts, Joris J.J. Dirckx

Abstract

Although most birds encounter large pressure variations during flight, motion of the middle ear components as a result of changing ambient pressure are not well known or described. In the present study, motion of the columella footplate and tympanic membrane (extrastapedius) in domestic chickens (Gallus gallus domesticus) under quasi-static pressure conditions are provided. Micro-CT scans were made of cadaveric heads of chickens under positive (0.25 kPa, 0.5 kPa, 1 kPa, and 1.5 kPa) and negative (−0.25 kPa, −0.5 kPa, −1 kPa, and −1.5 kPa) middle ear pressure. Both extrastapedius and columella footplate displacements show a non-linear S-shaped curve as a function of pressure indicating non-linear response characteristics of the middle ear components. The S-curve is also seen in mammals, but unlike in mammals, the lateral piston-like displacement of both the columella footplate and extrastapedius, which is caused by an increased middle ear pressure are smaller than the medial piston-like displacements, caused by a decreased middle ear pressure of the same magnitude. Columella footplate piston displacements are always smaller than the extrastapedius piston displacements, indicating the flexibility of the extracolumella. The cone-shape of the avian tympanic membrane with inverted apex in comparison to the mammalian tympanic membrane can cause the inverted shape of the pressure response curve.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KBFOor
via IFTTT

Input-output curves of low and high spontaneous auditory nerve fibers are exponential near threshold

Publication date: Available online 4 July 2018

Source: Hearing Research

Author(s): J. Wiebe Horst, JoAnn McGee, Edward J. Walsh

Abstract

Input-output (IO) properties of cochlear transduction are frequently determined by analyzing the average discharge rates of auditory nerve fibers (ANFs) in response to relatively long tonal stimulation. The ANFs in cats have spontaneous discharge rates (SRs) that are bimodally distributed, peaking at low (<0.5 spikes/s) and high (∼60 spikes/s) rates, and rate-level characteristics differ depending upon SR. In an effort to assess the instantaneous IO properties of ANFs having different SRs, static IO-curves were constructed from period histograms based on phase-locking of spikes to the stimulus waveform. These curves provide information unavailable in conventional average rate-level curves. We find that all IO curves follow an exponential trajectory. It is argued that the exponential behavior represents the transduction in the IHC and that the difference among ANFs having different SRs is predominantly a difference in gain attributed most likely to synaptic drive. © 2018 The authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRziXk
via IFTTT

Perception of noise-vocoded tone complexes: A time domain analysis based on an auditory filterbank model

Publication date: Available online 4 July 2018

Source: Hearing Research

Author(s): William P. Shofner, Hayley Morris, Mackenzie Mills

Abstract

When a wideband harmonic tone complex (wHTC) is passed through a noise vocoder, the resulting sounds can have spectra with large peak-to-valley ratios, but little or no periodicity strength in the autocorrelation functions. We measured judgments of pitch strength for normal-hearing listeners for noise-vocoded wideband harmonic tone complexes (NV-wHTCs) relative to standard and anchor stimuli. The standard was a 1-channel NV-wHTC and the anchor was either the unprocessed wHTC or an infinitely-iterated rippled noise (IIRN). Although there is variability among individuals, the magnitude judgment functions obtained with the IIRN anchor suggest different listening strategies among individuals. In order to gain some insight into possible listening strategies, test stimuli were analyzed at the output of an auditory filterbank model based on gammatone filters. The weak periodicity strengths of NV-wHTCs observed in the stimulus autocorrelation functions are augmented at the output of the gammatone filterbank model. Six analytical models of pitch strength were evaluated based on summary correlograms obtained from the gammatone tone filterbank. The results of the filterbank analysis suggest that, contrary to the weak or absent periodicity strengths in the stimulus domain, temporal cues contribute to pitch strength perception of noise-vocoded harmonic stimuli such that listeners' judgments of pitch strength reflect a nonlinear, weighted average of the temporal information between the fine structure and the envelope.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KKGvel
via IFTTT

Development of electrophysiological and behavioural measures of electrode discrimination in adult cochlear implant users

Publication date: Available online 4 July 2018

Source: Hearing Research

Author(s): Rajeev Mathew, Deborah Vickers, Patrick Boyle, Azhar Shaida, David Selvadurai, Dan Jiang, Jaime Undurraga

Abstract

The plasticity of the auditory system enables it to adjust to electrical stimulation from cochlear implants (CI). Whilst speech perception may develop for many years after implant activation, very little is known about the changes in auditory processing that underpin these improvements. Such an understanding could help guide interventions that improve hearing performance. In this longitudinal study, we examine how electrode discrimination ability changes over time in newly implanted adult CI users. Electrode discrimination was measured with a behavioural task as well as the spatial auditory change complex (ACC), which is a cortical response to a change in place of stimulation. We show that there was significant improvement in electrode discrimination ability over time, though in certain individuals the process of accommodation was slower and more limited. We found a strong relationship between objective and behavioural measures of electrode discrimination using pass-fail rules. In several cases, the development of the spatial ACC preceded accurate behavioural discrimination. These data provide evidence for plasticity of auditory processing in adult CI users. Behavioural electrode discrimination score but not spatial ACC amplitude was found to be a significant predictor of speech perception. We suggest that it would be beneficial to measure electrode discrimination in CI users and that interventions that exploit the plastic capacity of the auditory system to improve basic auditory processing, could be used to optimize performance in CI users.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MRVNv7
via IFTTT

Editorial Board

Publication date: July 2018

Source: Hearing Research, Volume 364

Author(s):

from #Audiology via ola Kala on Inoreader https://ift.tt/2KBFmGL
via IFTTT

The effects of the activation of the inner-hair-cell basolateral K+ channels on auditory nerve responses

Publication date: July 2018

Source: Hearing Research, Volume 364

Author(s): Alessandro Altoè, Ville Pulkki, Sarah Verhulst

Abstract

The basolateral membrane of the mammalian inner hair cell (IHC) expresses large voltage and Ca²⁺ gated outward K⁺ currents. To quantify how the voltage-dependent activation of the K⁺ channels affects the functionality of the auditory nerve innervating the IHC, this study adopts a model of mechanical-to-neural transduction in which the basolateral K⁺ conductances of the IHC can be made voltage-dependent or not. The model shows that the voltage-dependent activation of the K⁺ channels (i) enhances the phase-locking properties of the auditory fiber (AF) responses; (ii) enables the auditory nerve to encode a large dynamic range of sound levels; (iii) enables the AF responses to synchronize precisely with the envelope of amplitude modulated stimuli; and (iv), is responsible for the steep offset responses of the AFs. These results suggest that the basolateral K⁺ channels play a major role in determining the well-known response properties of the AFs and challenge the classical view that describes the IHC membrane as an electrical low-pass filter. In contrast to previous models of the IHC-AF complex, this study ascribes many of the AF response properties to fairly basic mechanisms in the IHC membrane rather than to complex mechanisms in the synapse.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MNQahG
via IFTTT

La parálisis cerebral. Diagnóstico e intervención logopédica

Publication date: July–September 2018

Source: Revista de Logopedia, Foniatría y Audiología, Volume 38, Issue 3

Author(s): Gerardo Aguado

from #Audiology via ola Kala on Inoreader https://ift.tt/2MNsB8u
via IFTTT

Revisión sistemática de la literatura sobre medidas aerodinámicas de la fonación

Publication date: July–September 2018

Source: Revista de Logopedia, Foniatría y Audiología, Volume 38, Issue 3

Author(s): Carlos A. Calvache-Mora, Marco Guzmán-Noriega

Resumen

Objetivo

El presente estudio muestra una revisión sistemática de la literatura relacionada con las aplicaciones clínicas e investigativas de las medidas aerodinámicas de la fonación: presión subglótica, flujo transglótico y resistencia glótica.

Metodología

La revisión se realizó en las bases de datos PubMed y Web Of Science con una ventana temporal 2000-2017. Todos los artículos revisados obtuvieron nivel I. Luego de realizar una evaluación crítica de la evidencia científica, fueron catalogados como estudios clínicos aleatorizados con diseños experimentales.

Resultados

Se entregan a partir de la asociación de las medidas aerodinámicas con seis categorías de análisis: a) como método objetivo de evaluación clínica; b) estudios con profesionales de la voz cantada y hablada; c) aplicaciones clínicas e investigativas en patologías laríngeas funcionales; d) investigaciones en diferentes grupos etarios; e) estudios en laringes caninas, y f) estudios en ejercicios con tracto vocal semiocluido.

Conclusiones

Se demuestra la objetividad de aplicar medidas aerodinámicas en los estudios de la voz patológica y profesional; las medidas aerodinámicas de la fonación pueden aplicarse en población tanto pediátrica como adulta, y en adultos mayores.

Abstract

Objective

The present study shows a systematic review of the literature, related to the clinical and investigative implementations of aerodynamic measurements of phonation: subglottic pressure, transglottic airflow and glottal resistance.

Method

The review was performed in PubMed and Web of Science databases with a time window 2000-2017. All articles reviewed obtained level I. After performing a critical assessment of the scientific evidence, articles were classified as randomized clinical studies with experimental designs.

Results

They are delivered from the association of aerodynamic measurements with six categories of analysis: a) as an objective method for clinical evaluation; b) studies with professional singing and speaking voice users; c) clinical and research implementations in functional laryngeal pathologies; d) research in different age groups; e) studies in canine larynx; and f) studies in voice exercises with semi-occluded vocal tract.

Conclusions

The objectivity of implementing aerodynamic measures in pathological and professional voice studies is demonstrated; the aerodynamic measures of phonation can be applied in the pediatric population, as well as in adults and the elderly.

from #Audiology via ola Kala on Inoreader https://ift.tt/2KKLcEV
via IFTTT

Estudio bibliométrico de la producción científica encontrada en Scopus y Web Of Science sobre rehabilitación vocal fisiológica

Publication date: July–September 2018

Source: Revista de Logopedia, Foniatría y Audiología, Volume 38, Issue 3

Author(s): Carlos A. Calvache-Mora, María A. Ríos-Ramírez

Resumen

Introducción

El presente estudio analiza la producción científica internacional encontrada en Scopus y Web of Science relacionada con la Corriente de Rehabilitación Vocal Fisiológica en el periodo 2006 a 2015.

Metodología

Estudio exploratorio-descriptivo con 3 fases de desarrollo: a) selección de palabras clave y criterios de búsqueda; b) búsqueda y sistematización de información; c) análisis de la información.

Resultados

La mayor producción científica se identifica en la herramienta de búsqueda Scopus bajo el criterio de búsqueda «voice therapy». Se analizaron un total de 167 publicaciones, realizando correlaciones a partir de las variables año, criterios de búsqueda, autores, factor de impacto por cuartil y por citación.

Conclusión

Existe alta correlación y grado de solapamiento entre ambas bases de datos. Sin embargo, Scopus comparada con Web of Science, con relación a las líneas de la Corriente de Rehabilitación Vocal Fisiológica y para el periodo estudiado, presentó un mayor porcentaje de producción científica. Las líneas con mayor impacto científico son «terapia Lee Silverman» y «ejercicios de la función vocal». «Ejercicios TVSO» y «terapia de voz resonante», con menos porcentaje de publicaciones, desde 2011 incrementan progresivamente factores de alto impacto.

Abstract

Introduction

The present study looks at the international scientific production found in Scopus and Web of Science, related to the Physiological Vocal Rehabilitation Current in the period 2006-2015.

Methodology

Exploratory-descriptive study with three phases of development: A) selection of keywords and search criteria; B) search and systematization of information; C) analysis of information.

Results

The highest scientific production is identified in the Scopus search tool under the “voice therapy” search criterion. A total of 167 publications were analyzed, making correlations from the year, search criteria, authors, impact factor by quartile and by citation variables.

Conclusion

There is a high correlation and degree of overlap between the two databases. However, Scopus compared to Web of Science, in relation to the Physiological Vocal Rehabilitation Current lines and for the period studied, presented a higher percentage of scientific production. The lines with the greatest scientific impact are “Lee Silverman therapy” and “vocal function exercises”. “SOVT exercises” and “resonant voice therapy”, with less percentage of publications, since 2011 progressively increase high impact factors.

from #Audiology via ola Kala on Inoreader https://ift.tt/2MNsvOa
via IFTTT