Summary: Regional cerebral blood flow was measured by the 133-xenon inhalation method during resting in 38 healthy men and 38 healthy women matched pairwise for age in the range 18-72 years. The results showed 11 % higher global flow level in the women in all ages. A sim ilar and significant regression of flow by age was seen for both sexes. The regional flow distribution also showed some sex-related differences. Frontal regions showed an asymmetry in the men with higher values on the right

Background and Purpose: Cerebral hypoperfusion has occasionally been reported during essential hypertension. We explored regional cerebral blood flow in a large series of neurologically asymptomatic hypertensive patients to determine relations among cerebral blood flow, concomitant main vascular risk factors, and the most common signs of end-organ damage.Methods: Regional cerebral blood flow was measured by the`33Xe inhalation method in 101 hypertensive patients without clinically apparent central nervous system involvement, including 39 mild to moderate untreated and 62 mild to severe treated patients.Results: Compared with age-and sex-matched normal control subjects, cerebral blood flow was significantly reduced in untreated hypertensive patients (P<.01) and to a lesser extent in treated patients (P=.047). Both regional and global cerebral blood flow reductions were observed in approximately one third of patients in both groups. Analysis of variance failed to show significant correlations between cerebral blood flow and total cholesterol concentration, mean arterial blood pressure, duration of disease, or the presence of retinopathy or left ventricular hypertrophy. In the treated group, the quality of control of hypertension significantly influenced both global cerebral blood flow (P=.007) and cerebrovascular resistance (P<.0001).Conclusions: Focal or diffuse cerebral hypoperfusion is present even in neurologically asymptomatic hypertensive patients, especially when untreated; good control of blood pressure may preserve cerebral

There has been clinical and experimental evidence that cholinergic compounds and precursors of choline are potentially useful in the treatment of dementia. Anticholinergic compounds have also been proposed as a possible acute model for pharmaco-EEG studies focussed on CNS aging. Single doses of scopolamine (0.25–0.75 mg i.m.) and a matching placebo were administered to 8 young healthy volunteers. Quantitative EEG recordings and neuropsychological testing were performed in baseline conditions prior to and 30, 90 and 120 min after drug administration. Scopolamine induced a dose-related increase of relative power in low- and high-frequency components and a decrease in the range 8.0–13.5 Hz and in total signal power. These modifications were found to be limited to the posterior scalp electrode derivations and were observed from the 90-min control onwards. Concomitantly, there was a significant impairment in the subjects’ response to neuropsychological testing after the administration of 0.50 and 0.75 mg of scopolamine. At a dose of 0.75 mg, volunteers complained about subjective symptoms which were definitely unpleasant. The effects of this dose on the EEG and the neuropsychological status did not differ significantly from those observed after a dose of 0.50 mg. As regards dose and tolerance, 0.50 mg of scopolamine administered intramuscularly appears to be a suitable dose for pharmaco-EEG studies.

Forty-two patients with probable Alzheimer’s disease (AD) and 18 elderly healthy controls underwent quantitative EEG (qEEG) and regional cerebral blood flow (rCBF; ¹³³Xe clearance) examinations. Correlations were sought between relative qEEG band powers and percent rCBF values in a posterior temporoparietal region of interest in either hemisphere. Moreover, stepwise discriminant analysis was applied to study the accuracy of the two techniques in differentiating AD from healthy ageing. rCBF and qEEG were correlated with one another, especially in the right hemisphere (p values ranging from <0.001 to <0.01). Significant correlations were found between Mini Mental State Examination (MMSE) and relative power of both the 2- to 6-Hz and the 6.5- to 12-Hz bands on either side (p < 0.001), and between MMSE and left rCBF (p < 0.005), while the correlation with right rCBF was poorer (p < 0.02). The statistical procedure identified the right values of both examinations for the discriminant analysis. Sensitivity of qEEG and rCBF employed together was 88% and specificity 89%, with a total accuracy of 88.3%. The unrecognized patients (n = 5) were affected by mild AD (4 scoring 3 at the Global Deterioration Scale and 1 scoring 4). qEEG alone showed an accuracy of 77% in the whole group and of 69% in mild AD, and rCBF alone an accuracy of 75% in the whole group and of 71% in mild AD. It is concluded that qEEG and rCBF examinations employed together are accurate tools to differentiate AD from normal ageing, although a lower degree of accuracy is achieved in mildly demented patients.

Regional cerebral blood flow was studied by means of the U3 Xe inhalation method hi 26 untreated and 10 treated patients with essential hypertension. The untreated subjects were divided into newly and previously diagnosed groups to assess the relation between regional cerebral blood flow and the duration of hypertension. The overall flow reduction was more marked in the frontal and temporal regions hi the previously diagnosed group, and this was attributed to pathological changes in the district served by the middle cerebral artery. Regional temporal lobe impairment was also noted in the newly diagnosed and treated subjects. A significant correlation was found between regional cerebral blood flow and mean arterial blood pressure. (Stroke 1987; 18:13-20)

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