Vestibular function prior to cochlear implantation in patients with non-syndromic hearing loss caused by CDH23 mutations: a retrospective case series.

Abstract

Background: Vestibular involvement in CDH23-related nonsyndromic hearing loss remains incompletely understood, particularly prior to cochlear implantation.

Aims/objectives: To evaluate vestibular function prior to cochlear implantation in patients with severe to profound non-syndromic hearing loss caused by CDH23 mutations.

Material and methods: We retrospectively evaluated vestibular function in seven patients with severe to profound non-syndromic hearing loss caused by CDH23 mutations who were scheduled for cochlear implantation. Vestibular assessment included caloric testing, ACS-cVEMP, BCV-oVEMP, and damped rotation testing, depending on age.

Results: Six patients had homozygous missense mutations, and one had compound heterozygous mutations in CDH23. Caloric testing revealed unilateral reduced responses in two patients (28.6%). Damped rotation testing, performed in four pediatric patients, showed a unilateral reduced response in one patient (25%). ACS-cVEMP demonstrated a unilateral reduced response in one patient (14.3%) and an absent response in another (14.3%). BCV-oVEMP, conducted in three patients, revealed a unilateral absent response in one patient (33.3%). Overall, unilateral vestibular dysfunction was identified in four of seven patients (57.1%).

Conclusions and significance: More than half of patients with CDH23-related non-syndromic deafness exhibited unilateral vestibular dysfunction prior to cochlear implantation, suggesting that preoperative vestibular assessment may be clinically relevant in this population.