The relation between proprioceptive ability and physical function in people with stroke, Parkinson's disease, and multiple sclerosis: a systematic review.

The relationship between proprioceptive ability and physical function is commonly assessed in people with stroke, Parkinson's disease, and multiple sclerosis to investigate the etiology of functional deficits. The primary aim of this systematic review was to evaluate the magnitude of this association. We also investigated whether the magnitude of these associations was influenced by 1) study sample size, 2) the pairing of body regions targeted by assessments of proprioceptive ability and physical function, 3) the proprioceptive sense assessed, and 4) the type of proprioceptive assessment (low-level proprioception; high-level proprioception). A total of 56 studies reporting 438 measures of association were included. The magnitude of the associations ranged from -0.31 to 0.93 (r and ρ), with 92% being positive (better proprioceptive ability associated with better physical function). Study sample size, pairing of assessments, and type of low-level proprioceptive assessment (detect, discriminate, match) did not systematically influence the direction or magnitude of the associations. Ninety-seven percent of assessments focused on low-level proprioception and kinesthesia (position and movement sense). When studies discussed their measures of association, 50% used language that implied causality. Despite a detailed breakdown of measures of association, no clear pattern emerged regarding the link between proprioceptive ability and physical function. Future studies in people with stroke, Parkinson's disease, and multiple sclerosis should 1) move away from simple measures of association to infer causation given that several interrelated and potentially confounding deficits coexist, and 2) assess various aspects of proprioception, including high-level proprioception, as they differentially contribute to physical function.