Auditory stimulus pattern discovering in paranoic schizophrenia patients.

Nine paranoic schizophrenia patients and nine controls participated in the study aimed at revealing differences in their ability to discover a pattern of auditory stimuli and to react to changes in environmental probability structure. Two kinds of auditory stimuli were used: high--1200 Hz (H) and low--800 Hz (L), both of 50 msec duration and 60 dB intensity. The experimental series were: series 1 (S1)--simple motor reaction to 50 L tones; series 2 (S2) and series 3 (S3) were identical--a cycle signal pattern (HHLHLL) of 102 tones. In S2 the instruction required choice motor reaction to L tone and in S3, also discovering the tone sequence and its verbal announcement. Patients discovered the stimulus pattern at the 28th and controls at the 30th signal. RT of patients in all series was longer than that of controls. Each of the factors "group" (controls/patients) and "experimental series" had a significant influence on RT. The possibility of interpreting these results as connected with an extrasensor mechanism dysfunction is discussed.