Visual object processing in schizophrenia: evidence for an associative agnosic deficit.

Early studies suggested visual form perception impairment in schizophrenia. To re-examine this claim and characterise the deficit neuropsychologically, 41 schizophrenic patients were administered tests sensitive to different levels of visual object perception and recognition. Intellectually well-preserved patients were examined separately on these and additional tests. Single case analysis was also applied to four patients showing varying degrees of general intellectual impairment. As a group, the patients showed little impairment on tests of early visual object perception, but greater impairment on higher-level visual processing tests, in particular object recognition and naming. This held true for patients with preserved general intellectual function. Single case analysis suggested that patients with schizophrenia have a selective deficit affecting object recognition and identification, with a pattern similar to visual associative agnosia in neurological patients.