vHIT and Caloric in auditory neuropathy spectrum disorder

What is it about?

Neuropathies of the eighth nerve may be due to primary demyelination or axonal diseases or by mixed disorder of the two resulting in normal cochlear functioning and affected afferent neural conduction in the auditory pathway. Since vestibular nerve is a part of the eighth nerve, there is a possibility of vestibular nerve also getting affected in individuals with auditory neuropathy. The aim of the study was to understand the correlation between caloric and video head impulse test (vHIT) results in individuals with auditory neuropathy. A total of three participants diagnosed as having auditory neuropathy, with no other otological or neurological problems were taken for the study. Bithermal caloric test and vHIT were administered for all the participants. In two of the participants with auditory neuropathy spectrum disorder (ANSD), hypo-functional caloric responses were observed along with reduced vestibuloocular reflex (VOR) gain and refixation saccades. However, third participant had hypofunctional caloric response along with normal VOR gain and absent refixation saccade.

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Photo by Martin Sanchez on Unsplash

Photo by Martin Sanchez on Unsplash

Why is it important?

In the present study, the caloric responses were found to be hypofunctional in all three participants suggesting vestibular deficits. Presence of hypofunctional caloric responses reduced VOR gain and refixation saccades suggested greater involvement of vestibular deficit.

Perspectives