An analysis of changes in cerebral blood flood velocities in depressive pseudo-dementia and Alzheimer disease patients.

BACKGROUND: Patients with pseudo-dementia are at particular risk of being labeled as Alzheimer dementia. We thus need better diagnostic methods. In this study, we evaluated the cerebral reactivity of the posterior cerebral arteries (PCAs) during visual stimulation by transcranial Doppler ultrasonography. METHODS: The study group consisted of 13 and 11 patients suffering from pseudo-dementia and Alzheimer disease (AD), respectively, and 10 healthy controls. Visual reactivity was defined as the differences of cerebral blood flow velocity (CBFv) against the visual stimulus. Mini Mental State Examination and Montgomery-Asberg Depression Rating Scales were used as psychometric tests. The transcranial Doppler ultrasonography device was applied for simultaneous recording of both PCAs. Obtained data were evaluated by Student t test, and 1-way analysis of variance tests, with a priori as P<0.05. RESULTS: Subjects with AD had a lower CBFv following visual stimuli (P<0.001). Mean CBFv throughout the procedure [P<0.001; right and left sides, in AD and depressive pseudo-dementia (DPD), respectively], velocity at rest (P<0.001 in each side for both groups), and velocity at stimulation (P<0.001; each side for both groups) on both PCAs were significantly lower in patients with AD and DPD than those of the controls. Compared with the controls, the relative (r) CBFvs (%) were found to be significantly lower in AD (P<0.05, P<0.01, for the right and left side, respectively). CONCLUSIONS: We have shown that CBFv decreased in patients with AD and DPD, but vasoneuronal activity was only impaired in patients with AD. On the other hand, although the results do not show significant differences between depressive and demented groups by TCD, further studies will be needed for differentiating these diseases.

Cerebral vasomotor reactivity of patients with acute ischemic stroke: Cortical versus subcortical infarcts: an Israeli-Turkish collaborative study.

BACKGROUND: Cerebral hemodynamic features of patients with different types of acute ischemic stroke are still obscure. We compared cerebral vasomotor reactivity (VMR) in acute cortical (CI) and subcortical (SI) brain infarcts. METHODS: Acute stroke patients (within 72 h of stroke onset) underwent transcranial Doppler and the Diamox test (1 g acetazolamide IV). The percent difference between blood flow velocities in the middle cerebral arteries before and after acetazolamide was defined as VMR%. CI and SI infarcts were confirmed by computerized tomography and/or magnetic resonance imaging. Clinical status and disability were assessed by means of the National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) respectively.VMR% values and stroke severity and disability parameters were compared between CI and SI groups using ANOVA and Pearson's correlation (r) coefficients. RESULTS: VMR% values of the ipsilateral side to the brain infarct in the CI group were significantly lower as compared with SI group (12.2+/-15.9% and 25.6+/-24.4% respectively, P=0.03). VMR% values in both groups were not correlated with stroke severity and disability (P<0.2). CONCLUSIONS: Our results suggest greater vulnerability of resistance arterioles in the setting of cortical gray matter infarcts. Although gray matter VMR is physiologically higher than white matter VMR, patients with acute CI have impaired cerebral vascular reserve.

The effects of hematocrit and age on transcranial Doppler measurements in patients with recent ischemic stroke.

BACKGROUND: The effects of age and hematocrit on transcranial Doppler (TCD) velocities have not been evaluated in a large patient group with recent ischemic stroke. AIM: This study assessed the effects of age and hematocrit on TCD measurements in patients with recent ischemic stroke compared to patients with non-vascular diseases. SETTINGS AND DESIGN: University Hospital, retrospective study. MATERIALS AND METHODS: TCD records and data files of 862 consecutive patients (mean age, 57+/-16 years) with various neurological diagnoses were reviewed retrospectively. The peak systolic, end diastolic and mean flow velocities (FV), systolic/diastolic ratios and pulsatility indices (PI) in the middle cerebral arteries were averaged and the effect of age and hematocrit values on these TCD values was studied. Independent samples t test, Pearson's coefficients of correlation, and linear regression test were used for statistical analysis. RESULTS: Among 862 patients, 413 were women (mean age, 53+/-17 years) and 449 were men (mean age, 60+/-13 years). Peak systolic and mean FV were higher and hematocrit concentration was lower in women compared to men (P< 0.001). The relation of TCD velocities with age and hematocrit was more remarkable in the group of patients with non-vascular neurological disorders. PI values demonstrated a significant correlation to age (r=+0.47) (P< 0.001), but did not change significantly with hematocrit level. CONCLUSIONS: It should be remembered that blood FV measured by TCD may be significantly affected by age and hematocrit level. However, there seems to be no significant association between TCD velocities and hematocrit in patients with a recent ischemic stroke.

Cerebral hemodynamic patterns with technetium Tc 99m exametazime single photon emission computed tomography and transcranial Doppler sonography: a validation study using visual stimulation.

OBJECTIVE: To assess whether a correlation between perfusion changes to visual stimulus on the bilateral occipital areas and blood flow velocity changes to visual stimulus in both posterior cerebral arteries is present. METHODS: Nine right-handed healthy subjects (4 women and 5 men; mean +/- SD age, 58.0 +/- 5.6 years) were included in the study. Visual stimulation was performed in room light with the subject's eyes open and looking around versus eyes closed as the stimulus-off condition. The blood flow velocities were recorded using transcranial Doppler sonography, and the regional cerebral blood flow measurements were recorded with the use of technetium Tc 99m exametazime and a single photon emission computed tomographic gamma camera system. Individual reactivity was defined as a relative increase of blood flow velocity and perfusion, which were calculated as percentage changes of baseline values. RESULTS: Visual stimuli produced a marked increase of blood flow velocity in both posterior cerebral arteries (35.2 +/- 2.3 cm/s; P < .001) without a significant side-to-side difference in all subjects as well as a marked increase of perfusion on both occipital areas (24.9 +/- 4.8 cm/s; P < .01). Moreover, there was a positive correlation between blood flow velocity changes and perfusion changes on both sides (r = 0.833; P < .01). CONCLUSIONS: The use of bilateral simultaneous Doppler recordings by means of a flow velocity averaging algorithm to a specific stimulus allows quantitative assessment of blood flow responses, and simple visual stimuli can be applied for different disorders to assess the vasomotor regulation that may result in measurable abnormal cerebral flow regulation even when clinically stabilized.