The medial vestibular nuclei, a vulnerable target in thiamine deficiency

Bilateral medial vestibular nuclei (MVN) is a common target in thiamine depletion and results in acute vestibular failure. Involvement of the MVN was present in 27 out of 38 brainstem sections reported in the largest thiamine deficiency autopsy cohort with Wernicke's encephalopathy. Serial clinical, imaging and vestibulo-ocular reflex gain measured with the video head impulse (vHIT) in one patient with acute thiamine deficiency. Low horizontal VOR gain correlated with an abnormal manual head impulse and with MRI evidence of MVN in an alcohol-dependent patient with low thiamine levels. The vertical VOR gain was either normal or mildly abnormal. Thiamine replacement and normal diet restored the VOR gain and MRI signal changes to normal. This single case study provides clinical-imaging correlation for symmetric MVN compromise in thiamine deficiency, its effect on the VOR gain and the favorable response to thiamine and diet replacement when identified early.