Sadler Christin M, Kami Aline Tiemi, Nantel Julie, Lommen Jonathan, Carlsen Anthony N
School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada.
School of Rehabilitation Therapy, Queen's University, Kingston, ON, Canada.
Front Neurol. 2022 Jun 14;13:913517. doi: 10.3389/fneur.2022.913517. eCollection 2022.
Transcranial direct current stimulation (tDCS) has been shown to modulate cortical motor excitability and improve bradykinesia symptoms in Parkinson's disease. It is unclear how targeting different cortical motor areas with tDCS may differentially influence upper limb function for individuals diagnosed with PD.
This study investigated whether anodal tDCS applied separately to the primary motor cortex and the supplementary motor area would improve upper limb function for individuals with Parkinson's disease. In addition, a startling acoustic stimulus was used to differentiate between the effect of stimulation on motor preparatory and initiation processes associated with upper limb movements.
Eleven participants with idiopathic Parkinson's disease performed two upper limb simple reaction time tasks, involving elbow extension or a button press before and after either anodal tDCS or sham tDCS was applied over the primary motor cortex or supplementary motor area. A loud, startling stimulus was presented on a selection of trials to involuntarily trigger the prepared action.
Anodal tDCS led to improved premotor reaction time in both tasks, but this was moderated by reaction time in pre-tDCS testing, such that individuals with slower pre-tDCS reaction time showed the greatest reaction time improvements. Startle-trial reaction time was not modified following tDCS, suggesting that the stimulation primarily modulated response initiation processes.
Anodal tDCS improved response initiation speed, but only in slower reacting individuals with PD. However, no differences attributable to tDCS were observed in clinical measures of bradykinesia or kinematic variables, suggesting that reaction time may represent a more sensitive measure of some components of bradykinesia.
经颅直流电刺激（tDCS）已被证明可调节皮质运动兴奋性并改善帕金森病的运动迟缓症状。目前尚不清楚tDCS靶向不同的皮质运动区域如何对被诊断为帕金森病的个体的上肢功能产生不同影响。
本研究调查分别应用阳极tDCS于初级运动皮层和辅助运动区是否会改善帕金森病患者的上肢功能。此外，使用一种令人吃惊的听觉刺激来区分刺激对与上肢运动相关的运动准备和启动过程的影响。
11名特发性帕金森病患者在阳极tDCS或假tDCS应用于初级运动皮层或辅助运动区之前和之后，执行两项上肢简单反应时间任务，包括肘部伸展或按键。在一些试验中呈现响亮、令人吃惊的刺激以非自愿地触发准备好的动作。
阳极tDCS在两项任务中均导致运动前反应时间改善，但这受到tDCS测试前反应时间的调节，使得tDCS测试前反应时间较慢的个体反应时间改善最大。tDCS后惊跳试验反应时间未改变，表明刺激主要调节反应启动过程。
阳极tDCS改善了反应启动速度，但仅在反应较慢的帕金森病个体中。然而，在运动迟缓的临床测量或运动学变量中未观察到tDCS所致的差异，表明反应时间可能是运动迟缓某些成分的更敏感指标。
