Centre of Precision Rehabilitation for Spinal Pain (CPR Spine), School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK.
Department of Sport and Exercise Sciences, Musculoskeletal Science and Sports Medicine Research Centre, Manchester Metropolitan University, Manchester, UK.
Eur J Pain. 2021 Sep;25(8):1668-1701. doi: 10.1002/ejp.1789. Epub 2021 Jun 25.
Numerous studies have examined the influence of pain on spinal reflex excitability, motor unit behaviour and corticospinal excitability. Nevertheless, there are inconsistencies in the conclusions made. This systematic review sought to understand the effect of pain on spinal and supraspinal projections to motoneurons and motor unit properties by examining the influence of clinical or experimental pain on the following three domains: H-reflex, corticospinal excitability and motor unit properties.
MeSH terms and preselected keywords relating to the H-reflex, motor evoked potentials and motor unit decomposition in chronic and experimental pain were used to perform a systematic literature search using Cumulative Index of Nursing and Allied Health Literature (CINAHL), Excerpta Medica dataBASE (EMBASE), Web of Science, Medline, Google Scholar and Scopus databases. Two independent reviewers screened papers for inclusion and assessed the methodological quality using a modified Downs and Black risk of bias tool; a narrative synthesis and three meta-analyses were performed.
Sixty-one studies were included, and 17 different outcome variables were assessed across the three domains. Both experimental and clinical pain have no major influence on measures of the H-reflex, whereas experimental and clinical pain appeared to have differing effects on corticospinal excitability. Experimental pain consistently reduced motor unit discharge rate, a finding which was not consistent with data obtained from patients. The results indicate that when in tonic pain, induced via experimental pain models, inhibitory effects on motoneuron behaviour were evident. However, in chronic clinical pain populations, more varied responses were evident likely reflecting individual adaptations to chronic symptoms.
This is a comprehensive systematic review and meta-analysis which synthesizes evidence on the influence of pain on spinal and supraspinal projections to motoneurons and motor unit properties considering measures of the H-reflex, corticospinal excitability and motor unit behaviour. The H-reflex is largely not influenced by the presence of either clinical or experimental pain. Whilst inhibitory effects on corticospinal excitability and motor unit behaviour were evident under experimental pain conditions, more variable responses were observed for people with painful musculoskeletal disorders.
许多研究都考察了疼痛对脊髓反射兴奋性、运动单位行为和皮质脊髓兴奋性的影响。然而，这些研究的结论并不一致。本系统评价旨在通过考察临床或实验性疼痛对以下三个领域的影响，来了解疼痛对脊髓和皮质脊髓投射到运动神经元和运动单位特性的影响：H 反射、皮质脊髓兴奋性和运动单位特性。
使用与慢性和实验性疼痛中的 H 反射、运动诱发电位和运动单位分解相关的 MeSH 术语和预选关键字，使用 Cumulative Index of Nursing and Allied Health Literature（CINAHL）、Excerpta Medica dataBASE（EMBASE）、Web of Science、Medline、Google Scholar 和 Scopus 数据库进行系统文献检索。两名独立的审查员筛选纳入的论文，并使用改良的 Downs 和 Black 偏倚风险工具评估方法学质量；进行了叙述性综合和三项荟萃分析。
共纳入 61 项研究，在三个领域评估了 17 项不同的结局变量。实验性和临床疼痛对 H 反射的测量均没有重大影响，而实验性和临床疼痛对皮质脊髓兴奋性似乎有不同的影响。实验性疼痛一致降低了运动单位放电率，这一发现与从患者中获得的数据不一致。结果表明，在通过实验性疼痛模型引起的紧张性疼痛中，对运动神经元行为的抑制作用是明显的。然而，在慢性临床疼痛人群中，观察到更多的变化反应，这可能反映了个体对慢性症状的适应。
这是一项全面的系统评价和荟萃分析，综合了疼痛对脊髓和皮质脊髓投射到运动神经元和运动单位特性的影响的证据，考虑了 H 反射、皮质脊髓兴奋性和运动单位行为的测量。H 反射在很大程度上不受临床或实验性疼痛的影响。虽然在实验性疼痛条件下观察到皮质脊髓兴奋性和运动单位行为的抑制作用，但在患有肌肉骨骼疼痛性疾病的人群中观察到更多的可变反应。
