Limited visual search on the WAIS Picture Completion test in patients with schizophrenia.

The Wechsler Adult Intelligence Scale was examined in 39 patients with schizophrenia, the visual cognitive task of Picture Completion showing the most impairment. In order to clarify the role of eye movements in Picture Completion, searching eye movements in 12 schizophrenic patients and 12 normal controls were recorded using an infrared eye-mark recorder. Schizophrenic patients as a group showed fewer eye fixations, and shorter total length of scan path than normal controls during the last 10 s of exposure to the picture. However, the patients who responded correctly, did so with a similar number of fixations and similar length of total scan path to those of normal controls. The patients who failed in the task took a significantly longer time for the first survey of the picture than the successful patients and normal controls. The less efficient strategy of visual search seen in the patients who failed might be a manifestation of poor reality testing and be related to frontal lobe dysfunction.

SPECT analysis of regional cerebral blood flow changes in patients with schizophrenia during the Wisconsin Card Sorting Test.

Single photon emission computed tomography (SPECT) images were obtained in 10 right-handed neuroleptic-treated schizophrenic patients and 10 healthy volunteers using Tc-99m-hexamethyl-propylenamine oxime (Tc99m-HMPAO) during performance of the Wisconsin Card Sorting Test (WCST) and at rest. None of the patients showed severe impairment on the WCST. The patient group showed a statistically insignificant trend to incur more unique errors. In both the patient and control groups, the left lateral prefrontal blood flow significantly increased during the WCST, as compared to during resting conditions. Only during the WCST, the patient group showed a significant regional cerebral blood flow (rCBF) decline in the left medial prefrontal cortex, as well as in the right side under both the test and resting conditions. This left medial prefrontal rCBF during the WCST correlated positively with the number of unique errors, although this correlation was statistically insignificant. The right fronto-parietal rCBF was significantly increased in the patient group under both the test and resting conditions. Moreover, in the left hippocampal region, the patient group showed a significant rCBF increase under resting conditions.

Left hypofrontality correlates with blunted affect in schizophrenia.

Regional cerebral blood flow (rCBF) during the resting state was measured using the 133Xe inhalation technique in 39 patients diagnosed as having schizophrenic disorder according to the DSM-III criteria and 30 age- and sex-matched healthy volunteers. All the patients were receiving neuroleptic medication. The bilateral hemispheric mean flow values in the schizophrenic patients decreased significantly and the relative flow distribution reduced significantly only in the left frontal region compared to the controls. The lower the left frontal blood flow in schizophrenics, the more pronounced were the negative symptoms including blunted affect, avolition-apathy and inattention. These results suggest that the negative symptoms in schizophrenics are related to left frontal lobe dysfunction.