Vestibular function in children with vestibulocochlear nerve aplasia/hypoplasia

Area of Science:

• Otolaryngology
• Neuroscience
• Pediatric Audiology

Background:

• Infants with vestibulocochlear nerve (VCN) hypoplasia/aplasia experience severe hearing loss, making them candidates for cochlear implantation (CI).
• The relationship between vestibular function and CI outcomes, and the utility of vestibular tests in surgical decision-making, remain unclear.

Purpose of the Study:

• To characterize vestibular function in pediatric patients diagnosed with VCN hypoplasia/aplasia prior to potential CI.
• To investigate if vestibular function assessment can inform CI candidacy and predict audiological outcomes.

Main Methods:

• Utilized bone-conducted cervical vestibular evoked myogenic potentials (BCcVEMP), video head impulse test (vHIT), and mini ice-water caloric tests (mIWC).
• Tested 42 ears across 23 pediatric patients between 2019 and 2022.
• Achieved high testability rates, with 83% of ears assessed using multiple vestibular methods.

Main Results:

• A significant portion of patients (61%) demonstrated normal vestibular function on at least one test, despite radiological VCN abnormalities.
• The presence of any normal vestibular response was associated with a twofold increase in the likelihood of achieving a measurable hearing threshold post-CI.
• BCcVEMP and vHIT emerged as the strongest predictors of favorable audiological outcomes.

Conclusions:

• Vestibular testing reveals functional pathways in many infants with VCN hypoplasia/aplasia, challenging purely radiological interpretations.
• Canal function appears to be a valuable predictor of auditory pathway integrity and potential audiological success following cochlear implantation.