Audio-vestibular Findings in a Patient with Pelizaeus- Merzbacher Disease.

Pelizaeus-Merzbacher disease (PMD) is an X-linked recessive rare disease condition in which audiological deficit is also observed. A 4-year-old male child with PMD underwent an audiological evaluation. The results suggested normal middle ear and outer hair cells functioning, with only peak I of the auditory brainstem response present until 30 dBnHL. Further, the cervical vestibular evoked myogenic potential showed delayed latencies with normal amplitudes. In this case report, we attempt to explain the audio-vestibular test results and correlate them with the pathophysiology. This is the first report on the cervical vestibular myogenic potentials in patients with PMD.

Measure of Central Vestibular Compensation: A Review.

The central vestibular compensation reduces vestibular symptoms and helps individuals improve balance affected by vestibular dysfunction. The video head impulse test provides an opportunity to study central vestibular compensation objectively. This study aims to methodically present existing information about the video head impulse test as a measure to evaluate central vestibular compensation in patients with unilateral vestibular dysfunction. Literature review comprised 12 research articles selected based on pre-set criteria and timeline (January 2010 to June 2020). The findings indicate that the appropriate video head impulse test measures to evaluate central vestibular compensation after the occurrence of temporary unilateral vestibular dysfunction are the improvement in vestibulo-ocular reflex gain. And, for permanent unilateral vestibular dysfunction are reduction in catch-up saccades percentage, velocity, amplitude, latency, and Perez and Rey score.