The Use of Video-Head Impulse Test in Different Head Positions in Vertical Nystagmus and Ataxia Associated with Probable Thiamine Deficiency.

The Use of Video-Head Impulse Test in Different Head Positions in Vertical Nystagmus and Ataxia Associated with Probable Thiamine Deficiency. Cerebellum. 2020 May 14;: Authors: Jorge A, Martins AI, Gouveia A, Lemos J Abstract Upward and downward bias of eye movement signals in the semicircular canals (SCC)- and/or otolith-related central pathways have been proposed to explain the occurrence of vertical nystagmus (downbeat nystagmus [DBN] and upbeat nystagmus [UBN]) and its frequent modulation with head position. Video-head impulse test (VHIT), usually performed in upright position, is a recent development for measuring SCC function. We performed longitudinal nystagmus and VHIT assessments in different head positions in a patient with probable thiamine deficiency, in order to explore a possible relationship between the positional behavior of vertical nystagmus and SCC function. Initially, UBN in upright position changed to DBN in prone position and remained relatively unchanged in supine position. This was associated with both anterior and posterior SCC hyperactive responses in upright position, and a relative enhancement of the anterior SCC responses in prone position and the posterior SCC responses in supine position. Over 1 year, in prone position, change from UBN to DBN and the enhancement of anterior SCC responses remained, while in supine position, UBN either decreased or changed to DBN, when compared to upright position. This w...
Source: Cerebellum - Category: Neuroscience Authors: Tags: Cerebellum Source Type: research