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Date of Graduation
5-7-2020
Document Type
Dissertation
Degree Name
Doctor of Audiology (AuD)
Department
Department of Communication Sciences and Disorders
Advisor(s)
Erin G. Piker
Christopher G. Clinard
Yingjiu Nie
Abstract
Objective: The purpose of this study was to assess age-related changes in the frequency tuning of the cervical vestibular evoked myogenic potential (cVEMP) and determine the optimal air conduction tone-burst stimulus frequency to elicit a cVEMP in the young, middle age, and older adult populations. Additionally, we performed wideband acoustic immittance measures to better delineate whether observed changes in frequency tuning properties of the cVEMP across the lifespan emanate from changes in the middle ear transfer function or from the otolith end organs.
Design: A cross-sectional study design included 98 healthy participants divided into 3 age groups of at least 29 participants in each: young adult (20 - 39 years), middle age adult (40 - 59 years), and older adult (≥ 60 years). Screening measures included otoscopy, tympanometry, and case history rule out a conductive hearing loss or vestibular dysfunction. cVEMPs were elicited using air conduction tone-bursts stimuli at 500 Hz, 750 Hz, and 1000 Hz presented at a 125 dB pSPL. Electromyographic (EMG) target ranges were established to ensure consistent and adequate generation of tonic muscle activity and average EMG was recorded to normalize the cVEMP response amplitudes. Wideband acoustic immittance measures were performed on each subject to assess the resonance frequency of the middle ear.
Results: No significant differences in mean middle ear resonant frequency were observed across age groups. The normalized cVEMP means and adjusted means with the middle ear resonant frequency as covariate were similar, however, all cVEMP analyses were performed on the adjusted means to control for individual differences of middle ear resonant frequency. There was a significant main effect of age group and cVEMP normalized response amplitude. Normalized cVEMP amplitudes for the younger adult and middle age adult groups to a 500 Hz and 750 Hz tone-burst stimuli were significantly larger compared to the older adult group. No significant differences in normalized cVEMP amplitude were observed at 1000 Hz across the three age groups. There was also a significant interaction of age group and stimulus frequency in the older adult group only. In the older adult group, the 1000 Hz tone-burst stimulus elicited the largest normalized cVEMP amplitude compared to both 500 Hz and 750 Hz, however, no significant differences in normalized amplitude between 500 Hz and 750 Hz were observed.
Conclusions: The observed shift in frequency tuning of the cVEMP in normal, healthy, older adults suggests the best stimulus frequency to elicit a response may be higher than the 500 Hz tone burst stimulus utilized clinically. The frequency tuning of the cVEMP in older adults may be attributed to peripheral vestibular system degeneration or saccular changes in the aging adult population.
Recommended Citation
Atabek, Paris M., "Effects of age and middle ear resonance on the frequency tuning of the cVEMP" (2020). Dissertations, 2020-current. 16.
https://commons.lib.jmu.edu/diss202029/16
