Hemiplegic shoulder pain affects ipsilesional aiming movements after stroke: a cross-sectional study.

Background: Hemiplegic shoulder pain (HSP) is common after stroke. The pain perception may exacerbate changes in the motor behavior of the ipsi-lesional upper limb, contributing to the functional decline of an individual's motor performance.

Objective: This study evaluates the influence of pain perception on the aiming movements performed with the ipsilesional upper limb in individuals with unilateral chronic stroke.

Methods: A cross-sectional study was conducted with 41 participants divided into three groups: 1) stroke with contralesional shoulder pain ≥ 3 by the Visual Numerical Pain Scale (SPSG; n = 13); 2) stroke no shoulder pain (nSPSG; n = 14); and 3) healthy control (CTG; n = 14) matched by sex and age. Individuals with stroke were matched for the severity of sensorimotor impairment by the Fugl-Meyer upper limb subscale and the injured hemisphere side. Stroke groups performed aiming movements with the ipsilesional upper limb and the CTG with the corresponding limb using a pen tip on the sensitive surface of a digitizing tablet. Performance across groups was compared by one-way analysis of variance, considering the time since injury as a covariate. The planning and execution variables of the movement trajectory were analyzed, and the significance was set at 5%.

Results: Trajectories of the SPSG were slower (p = .010; η = 0.22), were less smooth (p = .002; η = 0.30), had more directional error (p = .002; η = 0.28), and were less accurate (p = .034; η = 0.17) than the CTG. The nSPSG and CTG showed similar performance.

Conclusions: The perception of pain impairs aiming movements performed with the ipsilesional upper limb in individuals with unilateral chronic stroke.