Disordered spatiotemporal processing in schizophrenics.

Schizophrenics have been observed to process information slower than normal individuals. The present study evaluated spatiotemporal information processing by schizophrenics and normal controls by means of a contrast sensitivity task. Spatial frequency gratings (0.9, 3.8, 15 cycles/degree), temporally modulated at 0.0 stationary, 0.8, 3.25, 6.5, and 26.0 Hz, were presented to evaluate whether or not schizophrenics are deficient in processing patterns or temporal information. While the patterns were increasing linearly from 0% to 30% contrast, the subjects were required to discern when pattern or temporal changes first occurred. A multivariate Analysis of Variance revealed that schizophrenics were poorer at detecting temporal changes between 3.25 and 6.5 Hz, whereas they were able to detect patterns better on the low and poorer on the high spatial frequencies compared to normals. No differences were obtained for the stationary pattern. These results are discussed in terms of abnormal sensory gating occurring during the critical duration of temporal integration.