a1 Department of Psychology, University of Manchester
Some schizophrenics show anomalies in the frontal and temporal lobes. It is uncertain whether the cognitive deficits shown by Type I schizophrenics are caused directly by such anomalies, or by a deficit in the exertion of attentional effort. In this study, 16 acute schizophrenics, who broadly fitted the Type I characterization and their controls were given a battery of cognitive tests. The patients were impaired on effort-demanding tasks such as the Wisconsin Card Sorting Test, a verbal fluency test and the WAIS, which are susceptible in varying degrees to frontal, temporal and parietal lobe lesions. Patients were not disproportionately impaired, however, on a test of temporal memory and another of spatial memory, an impairment pattern that selectively reflects frontal and medial temporal lobe lesions respectively, nor were they impaired on a rate of forgetting task sensitive to medial temporal lobe lesions. These tasks were chosen not only because performance on them is selectively sensitive to frontotemporal lobe lesions, but also because it seems to depend on exerting minimum amounts of attentional effort. It is tentatively concluded that the cognitive deficits shown by Type I schizophrenics are caused by a problem in exerting attentional effort of unknown origin.
c1 Address for correspondence: Dr Andrew R. Mayes, Department of Psychology, University of Manchester, Manchester M13 9PL.