TRANSIENT IMPAIRMENT IN P50 AUDITORY SENSORY GATING INDUCED BY A COLD-PRESSOR TEST

Diminished gating of the auditory evoked response to repeated stimuli is a psychophysiological defect associated with schizophrenia and several other psychiatric illnesses. The P50 wave of the auditory evoked response to the second of paired stimuli is decreased in most normal subjects, whereas many psychotic subjects show significantly less decrement. The aim of this experiment was to test whether the cold-pressor test, which causes transient distress and pain accompanied by increased sympathetic activity, also causes a transient impairment in P50 auditory sensory gating in normal control subjects. Ten normal control subjects with normal gating of the P50 response immersed their hands in an ice water bath for 2 min. This cold-pressor test diminished P50 auditory gating in nine of these subjects, although the degree of impairment was highly variable among subjects. The impairment in gating was transient, with partial resolution by 30 min. The cold-pressor test was subjectively viewed as painful and also caused blood pressure to increase. Thus, a transient stressor can impair P50 auditory gating in some subjects.