[Dysfunction of tempo regulation in visual scanning and attention deficit in schizophrenia]

In order to investigate the relationship between the impatient behavior and attention deficit of schizophrenics, eye movements during visual scanning tasks were recorded by electro-oculogram in 50 chronic schizophrenics, 20 remitted schizophrenics and 50 normal controls. Ten rows of 9 to 11 star-marks, 1 degree in size, and separated 5 degrees from each other on the inner wall of Goldman's perimeter were used as the stimulus pattern. In the practice task, subjects were instructed to scan for 1 minute star-marks one by one in a definite order indicated by the arrows on the perimeter with an interval of 2 seconds, which was regulated by the sounding of a buzzer. Then in the slow task, subjects were instructed to scan and count star-marks with the same tempo as in the practice task without the cue from the buzzer. Immediately after the slow task, each subject was asked to estimate the passage of time and the personal impression of tempo regulation in the task. Horizontal and vertical vectors of eye movements were recorded electro-oculographically through electrodes at the outer canthi of each eye and from above and below the right eye (time constant 3 sec.). The average scanning tempo, the number of inappropriate fixation and the number of spontaneous blinking were analysed in both tasks. The test-retest reliability of the slow task was sufficiently high in 20 chronic schizophrenics. In the practice task, the average scanning tempo was almost the same among 3 groups, while in the slow task, the average scanning tempo of chronic schizophrenics was significantly faster than normal controls and remitted schizophrenics. The scanning tempo of chronic schizophrenics was faster at the first row and had the tendency to increase afterwards. The chronic schizophrenics estimated the tempo at which they scanned and the passage of time overly longer than normal controls and remitted schizophrenics. Thirteen items of BPRS (Brief Psychiatric Rating Scale) were significantly correlated with the average scanning tempo and the pattern of smooth pursuit eye movements with rectangular saccades was associated with the fastness of the average scanning tempo. The number of inappropriate fixation and the spontaneous blinking were significantly correlated with average scanning tempo in chronic schizophrenics and remitted schizophrenics but not in normal controls.(ABSTRACT TRUNCATED AT 400 WORDS)