Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Objectives: Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Design: Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. Results: For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. Conclusions: In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

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Using the Digits-In-Noise Test to Estimate Age-Related Hearing Loss.

Objective: Age-related hearing loss is common in the elderly population. Timely detection and targeted counseling can lead to adequate treatment with hearing aids. The Digits-In-Noise (DIN) test was developed as a relatively simple test to assess hearing acuity. It is a potentially powerful test for the screening of large populations, including the elderly. However, until to date, no sensitivity or specificity rates for detecting hearing loss were reported in a general elderly population. The purpose of this study was to evaluate the ability of the DIN test to screen for mild and moderate hearing loss in the elderly. Design: Data of pure-tone audiometry and the DIN test were collected from 3327 adults aged above 50 (mean: 65), as part of the Rotterdam Study, a large population-based cohort study. Sensitivity and specificity of the DIN test for detecting hearing loss were calculated by comparing speech reception threshold (SRT) with pure-tone average threshold at 0.5, 1, 2, and 4 kHz (PTA0.5,1,2,4). Receiver operating characteristics were calculated for detecting >20 and >35 dB HL average hearing loss at the best ear. Results: Hearing loss varied greatly between subjects and, as expected, increased with age. High frequencies and men were more severely affected. A strong correlation (R = 0.80, p

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Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Objectives: Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Design: Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. Results: For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. Conclusions: In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

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Using the Digits-In-Noise Test to Estimate Age-Related Hearing Loss.

Objective: Age-related hearing loss is common in the elderly population. Timely detection and targeted counseling can lead to adequate treatment with hearing aids. The Digits-In-Noise (DIN) test was developed as a relatively simple test to assess hearing acuity. It is a potentially powerful test for the screening of large populations, including the elderly. However, until to date, no sensitivity or specificity rates for detecting hearing loss were reported in a general elderly population. The purpose of this study was to evaluate the ability of the DIN test to screen for mild and moderate hearing loss in the elderly. Design: Data of pure-tone audiometry and the DIN test were collected from 3327 adults aged above 50 (mean: 65), as part of the Rotterdam Study, a large population-based cohort study. Sensitivity and specificity of the DIN test for detecting hearing loss were calculated by comparing speech reception threshold (SRT) with pure-tone average threshold at 0.5, 1, 2, and 4 kHz (PTA0.5,1,2,4). Receiver operating characteristics were calculated for detecting >20 and >35 dB HL average hearing loss at the best ear. Results: Hearing loss varied greatly between subjects and, as expected, increased with age. High frequencies and men were more severely affected. A strong correlation (R = 0.80, p

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Effects of Negative Middle Ear Pressure on Wideband Acoustic Immittance in Normal-Hearing Adults.

Objectives: Wideband acoustic immittance (WAI) measurements are capable of quantifying middle ear performance over a wide range of frequencies relevant to human hearing. Static pressure in the middle ear cavity affects sound transmission to the cochlea, but few datasets exist to quantify the relationship between middle ear transmission and the static pressure. In this study, WAI measurements of normal ears are analyzed in both negative middle ear pressure (NMEP) and ambient middle ear pressure (AMEP) conditions, with a focus on the effects of NMEP in individual ears. Design: Eight subjects with normal middle ear function were trained to induce consistent NMEPs, quantified by the tympanic peak pressure (TPP) and WAI. The effects of NMEP on the wideband power absorbance level are analyzed for individual ears. Complex (magnitude and phase) WAI quantities at the tympanic membrane (TM) are studied by removing the delay due to the residual ear canal (REC) volume between the probe tip and the TM. WAI results are then analyzed using a simplified classical model of the middle ear. Results: For the 8 ears presented here, NMEP has the largest and most significant effect across ears from 0.8 to 1.9 kHz, resulting in reduced power absorbance by the middle ear and cochlea. On average, NMEP causes a decrease in the power absorbance level for low- to mid-frequencies, and a small increase above about 4 kHz. The effects of NMEP on WAI quantities, including the absorbance level and TM impedance, vary considerably across ears. The complex WAI at the TM and fitted model parameters show that NMEP causes a decrease in the aggregate compliance at the TM. Estimated REC delays show little to no dependence on NMEP. Conclusions: In agreement with previous results, these data show that the power absorbance level is most sensitive to NMEP around 1 kHz. The REC effect is removed from WAI measurements, allowing for direct estimation of complex WAI at the TM. These estimates show NMEP effects consistent with an increased stiffness in the middle ear, which could originate from the TM, tensor tympani, annular ligament, or other middle ear structures. Model results quantify this nonlinear, stiffness-related change in a systematic way, that is not dependent on averaging WAI results in frequency bands. Given the variability of pressure effects, likely related to intersubject variability at AMEP, TPP is not a strong predictor of change in WAI at the TM. More data and modeling will be needed to better quantify the relationship between NMEP, WAI, and middle ear transmission. Copyright (C) 2016 Wolters Kluwer Health, Inc. All rights reserved.

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Using the Digits-In-Noise Test to Estimate Age-Related Hearing Loss.

Objective: Age-related hearing loss is common in the elderly population. Timely detection and targeted counseling can lead to adequate treatment with hearing aids. The Digits-In-Noise (DIN) test was developed as a relatively simple test to assess hearing acuity. It is a potentially powerful test for the screening of large populations, including the elderly. However, until to date, no sensitivity or specificity rates for detecting hearing loss were reported in a general elderly population. The purpose of this study was to evaluate the ability of the DIN test to screen for mild and moderate hearing loss in the elderly. Design: Data of pure-tone audiometry and the DIN test were collected from 3327 adults aged above 50 (mean: 65), as part of the Rotterdam Study, a large population-based cohort study. Sensitivity and specificity of the DIN test for detecting hearing loss were calculated by comparing speech reception threshold (SRT) with pure-tone average threshold at 0.5, 1, 2, and 4 kHz (PTA0.5,1,2,4). Receiver operating characteristics were calculated for detecting >20 and >35 dB HL average hearing loss at the best ear. Results: Hearing loss varied greatly between subjects and, as expected, increased with age. High frequencies and men were more severely affected. A strong correlation (R = 0.80, p

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Arterial Spin Labeling Perfusion Study in the Patients with Subacute Mild Traumatic Brain Injury

by Che-Ming Lin, Ying-Chi Tseng, Hui-Ling Hsu, Chi-Jen Chen, David Yen-Ting Chen, Feng-Xian Yan, Wen-Ta Chiu

Background

This study uses a MRI technique, three-dimension pulse continuous arterial spin labeling (3D-PCASL), to measure the patient’s cerebral blood flow (CBF) at the subacute stage of mild traumatic brain injury (MTBI) in order to analyze the relationship between cerebral blood flow and neurocognitive deficits.

Objective

To provide the relationship between cortical CBF and neuropsychological dysfunction for the subacute MTBI patients.

Methods

After MTBI, perfusion MR imaging technique (3D-PCASL) measures the CBF of MTBI patients (n = 23) within 1 month and that of normal controls (n = 22) to determine the quantity and location of perfusion defect. The correlation between CBF abnormalities and cognitive deficits was elucidated by combining the results of the neuropsychological tests of the patients.

Result

We observed a substantial reduction in CBF in the bilateral frontal and left occipital cortex as compared with the normal persons. In addition, there were correlation between post concussive symptoms (including dizziness and simulator sickness) and CBF in the hypoperfused areas. The more severe symptom was correlated with higher CBF in bilateral frontal and left occipital lobes.

Conclusion

First, this study determined that despite no significant abnormality detected on conventional CT and MRI studies, hypoperfusion was observed in MTBI group using 3D-PCASL technique in subacute stage, which suggested that this approach may increase sensitivity to MTBI. Second, the correlation between CBF and the severity of post concussive symptoms suggested that changes in cerebral hemodynamics may play a role in pathophysiology underlies the symptoms.

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