Correlation of cerebral hemodynamic changes during mental activity and recovery after stroke

Objective: To investigate the correlation between changes in cerebral funct ional activity during mental engagement and the potential for neurologic re covery after stroke. Background: Transcranial Doppler ultrasonography (TCD) makes it possible to detect the dynamic adjustment of cerebral perfusion r elated to functional neuronal changes. Methods: TCD monitoring of flow velo city changes in the middle cerebral artery of 29 ischemic stroke patients w as performed during an object recognition task. The study took place within 4 weeks from stroke onset. Based on recovery occurring after 2 months, the patients were divided into four groups depending on the side of hemispheri c lesion and the presence or absence of neurologic recovery. Ten healthy su bjects served as control subjects. Results: During the recognition task, co ntrol subjects showed a bilateral increase in flow velocity with respect to the rest phase (right side, 7.02 +/- 1.3%; left side, 6.65 +/- 1.1%), with no side-to-side difference. In patients who experienced recovery, a simila r pattern of bilateral activation was observed, irrespective of the side of the lesion. Conversely, in patients with no recovery, the increase of flow velocity was significantly higher on the side contralateral to the brain l esion (p < 0.0001) with respect to the lesion side. Performance during the recognition task was comparable in the four groups of patients. Conclusions : These findings suggest that satisfactory recovery from a neurologic defic it requires the persistence of functional activity in the damaged hemispher e despite the presence of an anatomic lesion. The possibility of obtaining early prognostic indications with TCD may be relevant for an early selectio n of patients with the best probability of benefiting from rehabilitation t herapy.