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Cerebral blood flow variation patterns have been studied in 20 control subjects and in 30 schizophrenics. This study demonstrates "hypofrontality" in schizophrenics and their lack of reactivity to strong verbal and somesthetic stimulations.

A group of clinical senile dementia patients underwent a series of cerebrovascular examinations. Some of them were standard examinations (fundus oculi, electroencephalogram, rheoencephalogram, cerebral angiogram and pneumonencephalogram) while the others were studying regional cerebral blood flow (rCBF) and modification of flow under fonctional tests (hypercapnia, hypocapnia and intravenous injection of 50 mg chl. papaverine) using the 133Xe clearance technique. The senile dementia group (III) was compared with 'normal' old patients group (I) and with patients suffering from sequelae of a previous stroke or from minor mental disorders (group II). Elderly subjects regarded as 'normal' often present alterations in usual vascular examinations but reveal a relative integrity of cerebral autoregulation. Some patients considered irreversibly 'sclerotic' still have a good grey matter flow (r1CBF) with real vasomotor possibilities. In each of the three groups of elderly subjects, there seemed to be a lack of correlation between the clinical symptoms and certain specific vascular examination.

Probenecid was administered to 7 unipolar depressed patients, 7 parkinsonians and 7 extrapyramidal patients with senile dementia matched for age and sex. Before and after the administration of probenecid, the levels of 5-hydroxindoleacetic acid (5HIAA) and homovanillic acid (HVA) were determined in the cerebrospinal fluid (CSF) of all patients in order to study the central turnover rate of serotonin and dopamine. Unipolar depressed patients showed a significantly lower increase in CSF 5HIAA levels after probenecid than parkinsonians. Patients with parkinsonism had a reduced increment of CSF HVA levels following probenecid administration when compared to unipolar depressed and extrapyramidal patients with senile dementia. The authors conclude that the biochemical study of CSF biogenic amines using the probenecid method can be used as a highly sensitive biological screening test for diagnosing Parkinson and depressive syndromes among an aging population of retarded, tremoring, rigid and hypokinetic patients.

Cerebral impedance changes (F changes) indicating cerebral blood flow variations in the central and precentral areas were measured with a rheographic technique in normal subjects preparing for and carrying out a motor task. The time course of the F changes was studied and several significant correlations were established between the amount of F changes, their distribution and the motor performance. Our findings confirm that frontal and premotor regions play an important part in decision making.