There is no TRR of brain activation induced by robotic hand passive movement: A functional NIRS study

The basic paradigm of rehabilitation is based on the brain plasticity, and for promoting it, test-retest reliability (TRR) of brain activation in which certain area of the brain is repeatedly activated is required. In this study, we investigated whether the robotic passive movement has the TRR of brain activation. Because active training has been shown to have TRR, but there are still arguments over the TRR by passive movement. In order to test TRR, ten repetitive sessions and various intervals (one day, three days, seven days, 23 days, 15 minutes, and six hours) were applied to five subjects, which had the same statistical power as applying two sessions to 50 subjects. In each session, three robot speeds (0.25Hz, 0.5Hz, and 0.75Hz) were applied to provide passive movement using the robot. The fNIRS signal (oxy-Hb) generated in the primary sensorimotor area (SM1) was measured on a total of 29 channels. At this time, we used activation maps and Intraclass correlation coefficient (ICC) values to examine the TRR and the effect of robot speeds and intervals on TRR. As a result, activation maps showed prominent variation regardless of robot speeds and interval, and the ICC value (=0.002) showed no TRR of brain activation for robotic passive movement.康复干预的基本范式基于脑可塑性（brain plasticity），而为促进这一过程，需确保特定脑区反复激活时的脑激活重测信度（test-retest reliability, TRR）。本研究旨在探究机器人辅助被动运动是否具备脑激活的重测信度：已有研究证实主动训练具备该重测信度，但被动运动是否拥有该特性仍存在争议。为验证重测信度，我们对5名受试者开展10次重复测试，并设置多种间隔时长（1天、3天、7天、23天、15分钟及6小时），该实验设计的统计效力等同于对50名受试者开展2次重复测试。在每一次测试中，我们通过机器人以3种不同速度（0.25Hz、0.5Hz及0.75Hz）为受试者提供被动运动刺激。我们通过共计29个通道，记录了初级感觉运动皮层（primary sensorimotor area, SM1）产生的功能性近红外光谱（functional near-infrared spectroscopy, fNIRS）信号中的氧合血红蛋白（oxy-Hb）信号。本研究采用激活图谱与组内相关系数（Intraclass correlation coefficient, ICC），对脑激活重测信度，以及机器人运动速度和间隔时长对重测信度的影响进行评估。结果显示，无论机器人运动速度与间隔时长如何，激活图谱均呈现显著变异；且ICC值为0.002，表明机器人辅助被动运动的脑激活并不具备重测信度。