Date of Award

Spring 1-1-2010

Document Type

Thesis

Degree Name

Doctor of Philosophy (PhD)

Department

Speech, Language & Hearing Sciences

First Advisor

Christina Yoshinana-Itano

Second Advisor

R. Stephen Ackley

Third Advisor

Sandra Gabbard

Abstract

Cochlear implantation has become an integral option for both children and adults with severe to profound degrees of sensorineural hearing loss, providing access to the auditory environment. While improvement in access to auditory information is required for appropriate spoken speech understanding in adults and for appropriate speech and language development in children with significant sensorineural hearing loss, the effects of cochlear implantation on the additional organs within the ear have not been fully evaluated. This study evaluated 40 cases (15 male, 25 female) between four and 60 years of age (M = 22.03, SD = 18.10). The goal of this study was to evaluate the presence of the vestibular evoked myogenic potential (VEMP) response in children and adults with severe to profound sensorineural hearing loss, and to determine the proportion of change to this response following implantation. Additional variables were evaluated to determine possible risk factors for absent VEMP responses both prior to and following cochlear implantation. While the VEMP responses were consistent with adults with normal hearing and vestibular systems prior to implantation, 47% of cases demonstrated a change from present to absent VEMP response following implantation, a significant decrease. No additional variables, with the exception of hearing loss stability prior to implantation, were found to be significant in these comparisons. The results of this study indicate the further need for vestibular evaluation within the population of cochlear implant candidates. Knowledge of the state of this system may provide additional information about the stability of the inner ear and should be used as an important counseling tool for clinicians of both pediatric and adult cochlear implant candidates. Due to the high proportion of change in the presence of the VEMP response, additional study of this response should be conducted to obtain greater understanding of how the vestibular system is affected by cochlear implantation surgery.

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