The Contributions of Age Related Changes in the Sound Localization Pathway to Central Hearing Loss

Overview

Age-related hearing loss, presbycusis, affects up to 50% of American adults. There are two main causes for presbycusis: 1) Progressive death of hair cells in the inner ear, and 2) Central hearing loss, or the reduced ability to decipher the sound source of interest from other competing sounds in a multi-source complex environment. The first cause is better understood and treatment options, such as hearing aids and cochlear implants, are available. However, central hearing loss is not as well understood and there is not a treatment available at this time. This study aims to advance our understanding of central hearing loss by evaluating the abilities of younger and older listeners in two primary outcome measures: to 1) neurologically process sound stimuli and 2) focus on conversational speech in the presence of spatially-separated competing background noise. A test using Auditory Brainstem Responses (ABR) will be used to evaluate the brain's response to clicking sounds.

This study will assess all waveform data, but will focus particularly on wave III. Sentence in noise tests will be used to assess each subject's ability to process speech in noisy situations. Both the ABR and sentence in noise tests are non-invasive and are commonly used in audiology practices to diagnosis and treat a variety of audiological pathologies.

Eligibility

Inclusion Criteria:

1. Subjects age ranges
   1. 21 years (inclusive) and 89years (inclusive)
2. Subjects exhibiting no poorer than a mild hearing loss, defined as hearing thresholds

   no worse than 40dBHL at any test frequency 250-4000 Hz based on pure tone audiometry

3. Subjects scoring 26 or higher on a screening measure of cognitive status (Montreal Cognitive Screening Assessment; MoCA)

Exclusion Criteria:

1. Patients outside the age range of 21-89
2. Patients with an air-bone gap greater than 10dBHL at any frequency
3. Patients who are decisionally challenged and/or unable to complete speech perception testing. These patients are excluded based on the study requiring behavioral responses to some tests
4. Patients with little command of the English language who are unable to understand and repeat back simple everyday English sentences.
5. Illiterate patients
6. Patients with neurodegenerative diseases.