Accession Number : ADP006103

Title :   The Effect of Mild Hypoxia on the Vestibular Evoked Response,

Corporate Author : DEFENCE AND CIVIL INST OF ENVIRONMENTAL MEDICINE DOWNSVIEW (ONTARIO)

Personal Author(s) : Fraser, W. D. ; Black, N. ; Eastman, D. E. ; Landolt, J. P.

Report Date : FEB 1988

Pagination or Media Count : 10

Abstract : The effect of hypoxia on the long-latency vestibular evoked response (VsER) was examined in eight sitting subjects who underwent intermittent 0.1 Hz sinusoidal rotation in complete darkness, while fixating on a small target light that rotated with the subject. Evoked responses were recorded during 10 minutes of rotational stimulation after breathing each gas mixture for a minimum of 25 minutes. It peaked close to the point of maximum velocity of the sinusoidal stimulus. This negative cortical potential decreased (i.e., it became less negative) with respect to the air control by 25.4% when the subjects were exposed to a 16.7% oxygen breathing mixture (altitude equivalent of 1900 m). No effect was seen with 18.7% (910 m) and 14.4% (2780 m) oxygen breathing mixtures. For intermittent counterclockwise (CCW) rotation, a positive potential developed, during air breathing, between the vertex and the linked ears. This amplitude decreased by 18.9% when breathing both the 18.7% and 16.6% oxygen gas mixtures (p < 0.01), and by 17.9% for a 14.4% oxygen mixture compared to the standard, air. (js)

Descriptors :   *EAR, AIR BREATHING, BREATHING GASES, DARKNESS, GASES, HYPOXIA, LIGHT, LINKAGES, MIXTURES, OXYGEN, ROTATION, STIMULATION(GENERAL), TARGETS, VELOCITY.

Subject Categories : Psychology

Distribution Statement : APPROVED FOR PUBLIC RELEASE