Is the clinical head impulse test helpful in cochlear implantation candidacy evaluation?

Abstract

Objective: Vestibular dysfunction is a known risk of cochlear implantation (CI). However, the utility of the physical exam to screen CI candidates for vestibular dysfunction is not well-studied. The objective of this study is to evaluate the preoperative role of the clinical head impulse test (cHIT) in subjects undergoing CI surgery evaluation.

Study design setting and subjects: We conducted a retrospective review of 64 adult CI candidacy cases between 2017 and 2020 at a tertiary health care center.

Methods: All patients underwent audiometric testing and evaluation by the senior author. Patients with an abnormal catch-up saccade contralateral to their worse hearing ear during cHIT were referred for formal vestibular testing. Outcomes included clinical and formal vestibular results, operated ear with regard to audiometric and vestibular results, and postoperative vertigo.

Results: Among all CI candidates, 44% (n = 28) reported preoperative disequilibrium symptoms. Overall, 62% (n = 40) of the cHITs were normal, 33% (n = 21) were abnormal, and 5% (n = 3) were inconclusive. There was one patient who presented with a false positive cHIT. Among the patients who endorsed disequilibrium, 43% had a positive preoperative cHIT. Fourteen percent of the subjects (n = 9) without disequilibrium had an abnormal cHIT. In this cohort, bilateral vestibular impairment (71%) was more common than unilateral vestibular impairment (29%). In 3% of the cases (n = 2), surgical management was revisited or altered due to cHIT findings.

Conclusion: There is a high prevalence of vestibular hypofunction in the CI candidate population. Self-reported assessments of vestibular function are often not congruent with cHIT results. Clinicians should consider incorporating cHITs as part of the preoperative physical exam to potentially avoid bilateral vestibular dysfunction in a minority of patients.