vHIT Testing for Presentation of Dizziness at a Comprehensive Stroke Center

During vHIT testing a commercially available mono-ocular video oculography system will be donned on the patient. (Interacoustics EyeSeeCam vHIT 3rd Generation Tests: VOR of lateral, RALP, \& LARP canals. SW: 3rd generation VE525 software. HW: laptop PC, lightweight monocular video goggles). Subjects will be instructed to maintain fixation at a target from 1 m distance. A study team member will deliver at least 5 head impulses per side (10-20° angle, duration 150-200 ms, peak velocity of \>150°/s) in the horizontal and vertical planes with unpredictable timing and direction. A neurotologist will then evaluate the VOR gain or the ratio of eye velocity over-head velocity. The presence of refixation (catch-up) saccades, either overt or covert, will be evaluated by the study team. In line with previous literature, the vHIT testing will be considered to be abnormal if VOR gain is \<0.8 in the presence of refixation saccades .

A standard neurologic evaluation will be performed including a National Institute of Health Stroke Scale and imaging if symptoms and NIHSS warrant.