Spatiotemporal Visual Processing in Schizophrenia

Studies examining visual processing in schizophrenia have provided inconsistent results. In this study, the authors measured static and dynamic visual contrast sensitivity (CS) in patients with schizophrenia (n=20) and control subjects (n=15). Extrapyramidal symptoms were evaluated with the Simpson-Angus scale. In the static condition, the patients with schizophrenia showed reduced CS in the spatial frequency range of 2.9–14.4 cycles per degree of visual angle (c/d). In the dynamic condition, CS loss was present over the whole range tested (0.5–14.4 c/d). Higher Simpson-Angus scores and higher doses of antipsychotic medication were associated with more severe CS deficits. These results suggest that the hypodopaminergic state induced by antipsychotic medication may produce parkinsonian visual impairments in schizophrenia patients.