Activation of healthy hemisphere in poststroke recovery. A transcranial Doppler study

The possible involvement of the healthy hemisphere in functional recovery in stroke hemiplegia is still controversial. This study of patients who had suffered ischemic stroke assessed circulatory changes in the healthy hemisphere by transcranial Doppler ultrasonography during opposition exercise of fingers that had recovered movement.

Measurements of flow velocity in the middle cerebral arteries were recorded in 12 recovered hemiplegic stroke patients and 12 healthy sex- and age-matched control subjects during a 2-minute sequential thumb-to-finger opposition task, alternatively performed with normal and recovered fingers. The effects of the motor task on heart rate, blood pressure, and end-tidal PCO2 were also evaluated.

With respect to the basal values, a comparable increase of flow velocity (%mean +/- SD) in the contralateral middle cerebral artery occurred in patients during movement of normal (9.7 +/- 2.7%) and recovered fingers (10.4 +/- 5.1%) and in controls (11.3 +/- 4.9%). However, in the middle cerebral artery ipsilateral to the hand performing the motor task, the increase of flow velocity was significantly higher (P < .001, two-way analysis of variance) during movement of the recovered hand in patients (10.5 +/- 4.6%) than during the movement of the normal hand in both patients (1.7 +/- 3.7%) and controls (1.8 +/- 4.5%). No significant difference of changes in heart rate, blood pressure, and end-tidal PCO2 was observed for patients or normal control subjects during the various phases of the study.

Our data suggest that activation of the healthy hemisphere contributes toward functional recovery of motor deficit after stroke and confirms the ability of transcranial Doppler ultrasonography to correlate cerebral artery flow dynamics with selective cerebral activation.