Psychological Medicine

Original Articles

Abnormal saccadic distractibility in patients with schizophrenia: a 99mTc-HMPAO SPET study

T. J. Crawforda1 c1, B. K. Puria1, K. S. Nijrana1, B. Jonesa1, C. Kennarda1 and S. W. Lewisa1

a1 Academic Unit of Neurosciences and Departments of Psychiatry and Nuclear Medicine, Charing Cross and Westminster Medical School, London; and School of Psychiatry and Behavioural Sciences, University of Manchester


Recent research has shown that some patients with schizophrenia have a severe impairment in the suppression of reflexive saccadic eye movements in the ANTI-saccade task. This saccadic distractibility has previously been found in patients with lesions of dorsolateral prefrontal cortex, implicating an abnormality of prefrontal cortex. The objective of the present study was to determine the contribution of these and other areas to the ANTI-saccadic abnormality in schizophrenia by functional neuroimaging. Using 99mtechnetium-HMPAO high resolution multidetector single-photon emission tomography, regional cerebral blood flow (rCBF) during performance of the ANTI-saccade eye-movement task was compared, by statistical parametric mapping, in ten male schizophrenic patients on stable antipsychotic medication who had a high distractibility error rate on the task, and eight similar patients who had normal distractibility error rates. Compared with the normal error group, the patients with high error rates showed significantly decreased rCBF bilaterally, in the anterior cingulate, insula, and in left striatum. These same patients also had increased perseverative errors on the Wisconsin Card Sort Test.


c1 Address for correspondence: Dr T. J. Crawford, Academic Neurosciences. Charing Cross and Westminster Medical School, Fulham Palace Road. London W6 8RF.