Response of the Translation Vestibulocular Reflex in Normal Human Subjects During Attempted Cancellation

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Authors
  1. Tomlinson, R.D.
  2. Cheung, R.
  3. Blakeman, A.
Corporate Authors
Defence and Civil Inst of Environmental Medicine, Downsview ONT (CAN);Toronto Univ, Toronto ONT (CAN) Dept of Physiology and Otolaryngology
Abstract
The inter-aural tanslational vestibulo-ocular relfex (IA-tVOR) was measured in eight normal subjects in response to sinusoidal acceleration head translations. Eye movements were recorded binocularly using an infrared video tracker (El-Mar). Results indicated that the tVOR is very robust and has a latency of less than 20ms. Subjects were asked to view targets located 20 and 100cm from the nasion during sinusoidal acceleration at frequencies of 0.5, 1,2,3, and 4Hz. The 20cm target could be either earth-fixed or could be moved with the head. In the latter case, the subjects attempted to cancel their IA-tVOR. The results were quite surprising. While the reflex sensitivity was seen to increase markedly with the 20cm target, as expected, cancellation results were better than expected. In other labs, the cancellation of the angular VOR had been found to only be possible at frequencies of 1Hz or less. However, we found that all of our subjects were able to cancel their IA-tVOR's quite effectively even at 2Hz with a reduction in sensitivity of greater than 50%.
Keywords
Translational Vestibulo-ocular reflex;tVOR;Visual tracking;Head movements
Report Number
DCIEM-CR-2002-007 — Contractor Report
Date of publication
07 Jan 2002
Number of Pages
18
DSTKIM No
CA020600
CANDIS No
517314
Format(s):
Document Image stored on Optical Disk

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