The effect of experimental and clinical musculoskeletal pain on spinal and supraspinal projections to motoneurons and motor unit properties in humans: A systematic review

Background and Objective Numerous studies have examined the influence of pain on spinal reflex excitability, motor unit behaviour corticospinal excitability. Nevertheless, there are inconsistencies in conclusions made. This systematic review sought to understand effect supraspinal projections motoneurons properties by examining clinical or experimental following three domains: H-reflex, excitability properties. Databases Data Treatment MeSH terms preselected keywords relating evoked potentials decomposition chronic were used perform a literature search using Cumulative Index Nursing Allied Health Literature (CINAHL), Excerpta Medica dataBASE (EMBASE), Web Science, Medline, Google Scholar Scopus databases. Two independent reviewers screened papers for inclusion assessed methodological quality modified Downs Black risk bias tool; narrative synthesis meta-analyses performed. Results Sixty-one included, 17 different outcome variables across domains. Both no major measures whereas appeared differing effects Experimental consistently reduced discharge rate, finding which was not consistent with data obtained from patients. The results indicate that when tonic pain, induced via models, inhibitory motoneuron evident. However, populations, more varied responses evident likely reflecting individual adaptations symptoms. Significance is comprehensive meta-analysis synthesizes evidence considering behaviour. H-reflex largely influenced presence either pain. Whilst under conditions, variable observed people painful musculoskeletal disorders.