Spatio-temporal disintegration of visual perception in schizophrenia as revealed by a novel cognitive task, the Searchlight Test.

We developed a novel computer-assisted psychological test (the Searchlight Test) in order to explore 'cognitive fragmentation' and its relation to thought disorder in schizophrenic patients. Participants were instructed to search geometric figures through a small hole (3 cm in diameter) on a display monitor by moving a mouse device and to reconstruct an image of the whole from the temporally and spatially fragmented visual stimuli.The cognitive function measures in 24 schizophrenic patients and 14 normal controls showed that the error rates of the recall task (drawing the figure from memory) and the recognition task (selecting the correct figure from several similar figures) were significantly higher in schizophrenic patients than in normal controls. The error rates of both tasks significantly correlated with disorganization syndrome in schizophrenia, but not with reality distortion or with psychomotor poverty syndrome.The present data obtained with the Searchlight Test suggest the spatio-temporal disintegration of visual perception in schizophrenia and its correlation with disorganization. This test appears to provide a useful tool for studying the pathophysiology of disorganization syndrome, thought disorder and the related cognitive dysfunction of schizophrenia.