Acupuncture stimulation causes bilaterally different microcirculatory effects in stroke patients

The aim of this study was to determine the effects of acupuncture stimulation (AS) in stroke patients by analyzing the pulsatile waveform and frequency content of skin blood-flow signals recorded simultaneously on the bilateral skin surface of the head. Laser Doppler flowmetry (LDF) signals were obtained in 18 stroke patients. Each assessment involved a 20-min baseline recording, a 20-min AS, and a further 20-min recording. Significant bilateral differences in LDF parameters were noted following AS, with an increased pulsatile component of the microcirculatory blood flow (MBF), decreased blood-flow resistance, and decreased MBF variability in the vascular beds on the stroke-affected side. Spectral analysis revealed that the vasodilation on the stroke-affected side could be partly attributed to decreased sympathetic neural activity. This is the first study to demonstrate the feasibility of evaluating the cerebral MBF conditions induced by AS in stroke patients by noninvasive LDF measurement. The present skull-intact measurement setup could aid the development of noninvasive detection techniques for determining bilateral differences in the cerebral MBF, and could thus become useful for the efficacy evaluation of treatment techniques for stroke. It might also promote understanding of the mechanisms underlying the responses and possible treatment efficacy of AS as applied to stroke patients.