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.