A comparison of psychiatric patients and normal controls on the integration of auditory stimuli

Temporal processing of sensory auditory information was investigated in 27 psychiatric patients and 29 normal controls by measuring forced choice thresholds for the right ear to bursts of noise stimuli of three different durations-4, 32, and 128 msec. Psychiatric patients were found to be 5 dB less sensitive than normal controls. A subsequent analysis compared the normal controls with three subgroups of psychiatric patients differentiated according to symptom profile. Those psychiatric patients whose main symptoms were affective showed a shallower threshold duration integration function than did normal controls. Patients whose major symptoms were delusions of persecution and depersonalization showed a slightly steeper slope than normal controls, whereas patients whose major symptom were hallucinations and lack of insight showed the steepest slope.