Preoperative Vestibular Function in Adults with Cochlear Implantation: Comparison between Prelingual and Poslingual Deafness / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Cochlear system and vestibular system have close relationship anatomically and developmentally. According to previous literatures, there are high incidences of vestibular dysfunction in subjects with severe hearing loss. The aim of this study is to validate the status of vestibular function in adults with profound hearing loss, and to compare the status of vestibular function between pre-lingual and post-lingual deaf. SUBJECTS AND METHOD: Vestibular function of 59 patients who had profound hearing loss was reviewed retrospectively. Patient's information and audiometry, Korean version Central Institute for the Deaf (KCID) scores, caloric test, rotation chair test and vestibular evoked myogenic potential (VEMP) were analyzed. The subjects were divided into two groups, prelingual deaf (pre-LD, n=12) and postlingual deaf (post-LD, n=47). We analyzed the difference between two groups. RESULTS: Fifty nine point six percent of patients showed hypo-function in caloric test. In the rotational chair test, abnormality of step velocity gain (43.1%), time constant (51.8%), sinusoidal harmonic acceleration (SHA)-gain (53.4%), SHA-phase lead (29.1%) and SHA-asymmetry (23.6%) were found. There was unilateral (20.0%) and bilateral (37.5%) hypo-function when VEMP was tested. Between pre-LD and post-LD groups, VEMP test revealed statistically significant difference between two groups (p=0.020). Post-LD groups had more patients of unilateral or bilateral hypofunction in VEMP test. The KCID score showed no significant correlation with vestibular functions. CONCLUSION: The patients of bilateral profound hearing loss showed unilateral or bilateral vestibular functional abnormality despite of no dizziness. Prevalence of lateral canal dysfunction does not seem to be different between pre-LD group and post-LD group. And post-LD groups have higher probability of saccular dysfunction than pre-LD.