FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute

Report No: DOT/FAA/AM-63/29

Title and Subtitle: Task-control of arousal and the effects of repeated unidirectional angular acceleration on human vestibular responses

Report Date: November 1963

Authors: Collins WE

Abstract: Subjects were exposed to a 10-day habituation series of 200 CW accelerations in total darkness while performing attention-demanding tasks. Decelerations were sub-threshold. Preliminary and post-tests indicated that slow-phase nystagmus and duration of the ocular response declined [bidirectionally] as a function of the habituation trials, but frequency of nystagmus increased during stimulus period and for a few seconds thereafter. These changes were approximately equal for both CW and CCW stimulation.

Measurements of subjective velocity were obtained during several pre- and post-trials but never during the habituation series. A decline in the intensity of the sensation to CW acceleration, but not to CCW stimulation, was produced by the habituation series. A second post-test given after one month with no intervening stimulation showed little or no restoration of nystagmus. However, the subjective reaction demonstrated a clear, albeit incomplete pattern of recovery.

Key Words: vestibular function, adaptation, nystagmus, psychology, sensory psychology.

No. of Pages: 30