Assessment of otolith mediated neural reflexes through cervical and ocular vestibular evoked myogenic potentials in individuals with auditory neuropathy spectrum disorders. (2nd April 2016) - Singh, Niraj Kumar
Abstract: Auditory neuropathy spectrum disorder (ANSD) is characterized by abnormal auditory neural function in the presence of normal cochlear function. Although the presence of vestibular dysfunction has been reported in ANSD through sporadic studies, cervical and ocular vestibular evoked myogenic potentials (cVEMP and oVEMP) were sparingly explored in the same individuals with ANSD. Thus, the present study aimed at investigating otolith modulated neural function in individuals with ANSD. A static group comparison research design was used. cVEMP and oVEMP were elicited by 500-Hz tone bursts from 31 individuals with ANSD and 31 age- and gender-matched healthy controls. Results showed that the response prevalence was less than 20% for both potentials. The present responses were characterized by significant prolongation of later peaks and inter-peak latency intervals and significantly reduced amplitudes compared to the controls ( p < 0.001). Both potentials exhibited larger asymmetry ratios compared to the controls, but only cVEMP asymmetry ratio reached a statistically significant level. There was no association of cVEMP and oVEMP response prevalence with the presence of vestibular symptoms. Abnormal or absent responses in the majority of individuals suggest superior and inferior vestibular nerve dysfunction in ANSD. A detailed vestibular evaluation, in addition to the auditory system assessment, is strongly recommended in ANSD.