Investigation of Anatomical Correlates of Speech Discrimination

Study Overview
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Brief Summary
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Understanding speech is essential for good communication. Individuals with hearing loss and poor speech discrimination often have little success with hearing aids because amplifying sound improves audibility, but not clarity of the speech signal. The purpose of this study is to determine the relative importance of the sensory cells of the inner ear and auditory neurons on speech discrimination performance in quiet and in noise. This information may be used as a predictor of hearing aid benefit. The investigators expect to find decreased speech understanding ability resulting from both loss of sensory cells and the loss of auditory neurons.

Official Title
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Investigation of Anatomical Correlates of Speech Discrimination

Conditions
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Sensorineural Hearing Loss

Intervention / Treatment
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* Device: Hearing Aid fitting


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Normal hearing to moderate sensorineural hearing loss Sufficient English proficiency to complete speech discrimination testing in English Exclusion Criteria: Hearing loss less than a 45 dB HL pure tone average (average hearing thresholds at 500, 1000 and 2000 Hz) Conductive hearing loss Neurodegenerative disease

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 100 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| low HIN difficulty- anesthetized<br>Subjects with normal OHC function and who will be undergoing an previously scheduled anesthetized procedure will be assigned into 2 groups based on their self-perceived HIN difficulty (high and low difficulty), and then undergo a test battery consisting of auditory threshold tests, objective HIN assays, OHC measurements, cognitive processing, and central auditory processing evaluations. Immediately after anesthetization, electrocochleography (ECochG) will be used to measure CAP amplitudes, which will be correlated with measurements obtained from unanesthetized subjects as described below. This aim will determine the optimal CAP recording method with the strongest correlation with HIN performance in humans | |
| high HIN difficulty- anesthetized<br>Subjects with normal OHC function and who will be undergoing an previously scheduled anesthetized procedure will be assigned into 2 groups based on their self-perceived HIN difficulty (high and low difficulty), and then undergo a test battery consisting of auditory threshold tests, objective HIN assays, OHC measurements, cognitive processing, and central auditory processing evaluations. Immediately after anesthetization, electrocochleography (ECochG) will be used to measure CAP amplitudes, which will be correlated with measurements obtained from unanesthetized subjects as described below. This aim will determine the optimal CAP recording method with the strongest correlation with HIN performance in humans | |
| Hearing Aid fitting: MAD<br>Microphone adaptive directionality (MAD) feature will be activated, the WDC set to linear, and the DNR minimized | Device: Hearing Aid fitting<br>* Subjects with hfPTAs ranging from 0-55 dB HL will be recruitedwith 100 persons self-reporting difficulty HIN (> 50% of the time), and 100 persons reporting little difficulty HIN (< 50% of the time) will be randomly assigned to one of five groups (n = 200) based on enabled HA features using an online random assignment tool. Unaided HIQ and HIN assessments will be conducted in the sound field, and baseline DPOAE and CAP assessments will be measured. Subjects will be fit with binaural premium level receiver-in-the canal HAs (Phonak B90 or equivalent model at the start of the study) with 56 dB SPL gain receivers, using closed domes, and programmed to NAL-NL2 target gain, and randomly assigned to the groups.<br>|
| Hearing Aid fitting: WDC<br>Wide dynamic compression (WDC) feature will be set to target levels, the MAD feature set to omnidirectional, and the DNR minimized. | Device: Hearing Aid fitting<br>* Subjects with hfPTAs ranging from 0-55 dB HL will be recruitedwith 100 persons self-reporting difficulty HIN (> 50% of the time), and 100 persons reporting little difficulty HIN (< 50% of the time) will be randomly assigned to one of five groups (n = 200) based on enabled HA features using an online random assignment tool. Unaided HIQ and HIN assessments will be conducted in the sound field, and baseline DPOAE and CAP assessments will be measured. Subjects will be fit with binaural premium level receiver-in-the canal HAs (Phonak B90 or equivalent model at the start of the study) with 56 dB SPL gain receivers, using closed domes, and programmed to NAL-NL2 target gain, and randomly assigned to the groups.<br>|
| Hearing Aid fitting: DNR<br>Digital noise reduction (DNR) set to maximum, MAD set to omnidirectional, and WDC set to linear | Device: Hearing Aid fitting<br>* Subjects with hfPTAs ranging from 0-55 dB HL will be recruitedwith 100 persons self-reporting difficulty HIN (> 50% of the time), and 100 persons reporting little difficulty HIN (< 50% of the time) will be randomly assigned to one of five groups (n = 200) based on enabled HA features using an online random assignment tool. Unaided HIQ and HIN assessments will be conducted in the sound field, and baseline DPOAE and CAP assessments will be measured. Subjects will be fit with binaural premium level receiver-in-the canal HAs (Phonak B90 or equivalent model at the start of the study) with 56 dB SPL gain receivers, using closed domes, and programmed to NAL-NL2 target gain, and randomly assigned to the groups.<br>|
| Hearing Aid fitting: Positive control<br>All hearing aid features enables | Device: Hearing Aid fitting<br>* Subjects with hfPTAs ranging from 0-55 dB HL will be recruitedwith 100 persons self-reporting difficulty HIN (> 50% of the time), and 100 persons reporting little difficulty HIN (< 50% of the time) will be randomly assigned to one of five groups (n = 200) based on enabled HA features using an online random assignment tool. Unaided HIQ and HIN assessments will be conducted in the sound field, and baseline DPOAE and CAP assessments will be measured. Subjects will be fit with binaural premium level receiver-in-the canal HAs (Phonak B90 or equivalent model at the start of the study) with 56 dB SPL gain receivers, using closed domes, and programmed to NAL-NL2 target gain, and randomly assigned to the groups.<br>|
| Hearing Aid fitting: Negative control<br>All hearing aid features disabled | Device: Hearing Aid fitting<br>* Subjects with hfPTAs ranging from 0-55 dB HL will be recruitedwith 100 persons self-reporting difficulty HIN (> 50% of the time), and 100 persons reporting little difficulty HIN (< 50% of the time) will be randomly assigned to one of five groups (n = 200) based on enabled HA features using an online random assignment tool. Unaided HIQ and HIN assessments will be conducted in the sound field, and baseline DPOAE and CAP assessments will be measured. Subjects will be fit with binaural premium level receiver-in-the canal HAs (Phonak B90 or equivalent model at the start of the study) with 56 dB SPL gain receivers, using closed domes, and programmed to NAL-NL2 target gain, and randomly assigned to the groups.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Regression analysis | Regression analysis will be used to look for a correlation between measures of sensory cell and auditory neuron survival and speech recognition performance. | June 2024 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hair cell, hearing aid, hearing loss, auditory nerve, synaptopathy, Outer hair cell, Otoacoustic emission