Parker Rosalind S, Lewis Gwyn N, Rice David A, McNair Peter J
*Health and Rehabilitation Research Institute, Auckland University of Technology †Waitemata Pain Service, Department of Anaesthesiology and Perioperative Medicine, North Shore Hospital, Auckland, New Zealand.
Clin J Pain. 2017 Mar;33(3):222-230. doi: 10.1097/AJP.0000000000000392.
Previous studies have shown a tendency for reduced motor cortex inhibition in chronic pain populations. People with chronic pain also routinely demonstrate motor deficiencies, including skill learning. The goals of the current study were to (1) provide a thorough analysis of corticomotor and intracortical excitability in people with chronic arthritic hand pain, and (2) examine the relationship between these measures and performance on a motor skill learning task.
Twenty-three people with arthritic hand pain and 20 pain-free controls participated in a cross-sectional study. Transcranial magnetic stimulation was used to assess corticomotor and intracortical excitability of the first dorsal interosseus muscle. Participants then completed a 30-minute motor skill training task involving the index finger of the same hand.
Hand arthritis participants showed evidence of reduced intracortical inhibition and enhanced facilitation, which correlated with duration of hand pain. Arthritis participants were initially poorer at the motor skill task but over the total training time performance was equivalent between groups. There were no associations found between measures of intracortical excitability and motor skill learning.
Our findings are the first to provide evidence of cortical disinhibition in people with painful arthritis, as previously demonstrated in other chronic pain populations. Cortical excitability changes may progress the longer pain persists, with increased pain duration being associated with greater cortical disinhibition. There was no evidence that these changes in cortical excitability are related to impaired motor function or skill learning.
以往研究表明，慢性疼痛人群存在运动皮层抑制减弱的趋势。慢性疼痛患者通常也表现出运动缺陷，包括技能学习方面。本研究的目的是：（1）全面分析慢性关节炎手部疼痛患者的皮质运动和皮质内兴奋性；（2）研究这些指标与运动技能学习任务表现之间的关系。
23名患有关节炎手部疼痛的患者和20名无疼痛对照者参与了一项横断面研究。采用经颅磁刺激评估第一背侧骨间肌的皮质运动和皮质内兴奋性。参与者随后完成了一项涉及同一只手食指的30分钟运动技能训练任务。
手部关节炎患者表现出皮质内抑制减弱和易化增强的证据，这与手部疼痛的持续时间相关。关节炎患者在运动技能任务开始时表现较差，但在整个训练时间内，两组的表现相当。未发现皮质内兴奋性指标与运动技能学习之间存在关联。
我们的研究结果首次为疼痛性关节炎患者存在皮质去抑制现象提供了证据，此前在其他慢性疼痛人群中也有过相关证明。随着疼痛持续时间延长，皮质兴奋性变化可能会加剧，疼痛持续时间增加与更大程度的皮质去抑制相关。没有证据表明皮质兴奋性的这些变化与运动功能受损或技能学习有关。
