Mental Tasking and Caloric-Induced Vestibular Nystagmus Utilizing Videonystagmography

The purpose of this study was to quantify the effects of mental tasking on measures of the caloric vestibulo-ocular reflex utilizing videonystagmography as the measurement technique.

A within-subjects repeated-measures design was utilized. Sixteen healthy adults were evaluated (13 women, 3 men; ages 19-31 years). Each participant underwent bithermal caloric irrigation at 2 separate counterbalanced visits. At 1 visit mental tasking was utilized, whereas the other visit did not utilize mental tasking. The following outcomes were measured for each visit: peak slow-phase velocity (SPV), response duration, peak SPV latency, and eye blink artifact.

No significant difference was seen for tasking versus no tasking with peak SPV, peak latency, or response duration. A significant difference was seen for the amount of eye blink artifact, with significantly more eye blinks present for the tasking condition.

Results could indicate mental tasking does not affect the important measure of SPV. Moreover, increased eye blink artifact with tasking could obscure the clinician's ability to read the nystagmograph. However, this investigation is limited to the healthy young adult population, and more studies should be performed to corroborate the presented evidence.