Differences in the beat-to-beat parameters of skin-surface pulsatile laser-Doppler waveforms between stroke and normal subjects

Abstract

Walking can help improve the recovery after stroke. The present study used skin-surface laser-Doppler flowmetry (LDF) measurements and beat-to-beat waveform analysis with the aim of discriminating the microcirculatory blood flow (MBF) characteristics in stroke subjects subdivided into two groups according to their walking ability. Five-minute LDF measurements were performed in the following groups: Group A (cannot walk independently; n = 17), Group B (can walk independently; n = 11), and Group C (healthy controls; n = 17). The pulse width (PW) and foot delay time (FDT) and their coefficients of variation (PWCV and FDTCV, respectively) were calculated for the beat-to-beat LDF waveform. The FDT in Group A and the blood-pressure-normalized PW in Group C were significantly longer than the corresponding values in the other groups, and PWCV and FDTCV were significantly larger in Group C than in Group A. To our knowledge this is the first study demonstrating the feasibility of using a beat-to-beat LDF waveform index to discriminate between stroke subjects with different walking abilities and between stroke and normal subjects. It provides a noninvasive and real-time method for discriminating MBF characteristics, and thus could aid the development of an index for the early detection of stroke or for evaluating the recovery condition in stroke patients.