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

Abstract

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.

Figure 1.

MRI images showing diffuse altered signal intensity change hypointense on T1 (A), hyperintense on T2 (B), FLARE in the white matter of both the cerebral hemispheres (C), both dentate nuclei and BILATERAL (B/L) cerebellar hemispheric white matter (D). Subtle symmetrical T2/Fluid-attenuated inversion recovery (FLAIR) hyperintensity is also seen along both the corticospinal tract (CST) in the pons, median pontine raphe and B/L CTT (D). Thinning of the corpus callosum with (F) MRS showing increased N-acetylaspartate (NAA) peak (E). CTT, central tegmental tract; MRI, magnetic resonance imaging.

Figure 2.

Auditory brainstem recording of both right and left ears with rarefaction and condensation polarity showing CM (at 90 dBnHL) and peak I (from 90 dBnHL to 30 dBnHL) (A) and cervical vestibular evoked myogenic potential for both right and left ears (B).