LXXXIII Subjective Responses and Nystagmus following Repeated Unilateral Caloric Stimulation

Abstract

Forty unilateral caloric irrigations were administered in a habituation series to each of 2 groups of subjects. One group was tested in total darkness. Subjects in the 2nd group were stimulated in illumination and actively attempted to control and suppress their eye movements by means of visual fixation. Pre- and posttests were administered (always in total darkness) in which both directions of response were elicited. In all cases, tasks were assigned to subjects to maintain alertness. The nystagmic reaction was altered as a result of the habituation series, but the change was different for the 2 groups. After 1 mo. of rest, there was no apparent recovery of the response toward the pretest level for either group. Subjective reactions declined in intensity for both groups, but showed recovery after a 1-mo. rest period.