Centrality of Pain in Post-Stroke Shoulder Pain: A Case-Control Study

This study aimed to examine whether centrality of pain behavior differs between individuals with post-stroke shoulder pain (PSSP) and those with non-hemiplegic chronic shoulder pain.

Participants with a history of cerebrovascular accident (CVA) were assigned to the PSSP group, whereas those without a history of CVA were classified as the non-hemiplegic shoulder pain group. Pain intensity was measured with the numeric pain scale. The Centrality of Pain Scale (COPS) assessed pain centralizing behavior. Shoulder pain and functional status were evaluated using the Shoulder Pain and Disability Index (SPADI).

A total of 130 participants were included: 65 individuals with PSSP (mean age = 61.84 ± 11.47) and 65 with non-hemiplegic shoulder pain (mean age = 57.09 ± 11.80). The PSSP group demonstrated significantly higher COPS scores (MD = -3.21; 95% confidence interval [CI] = -5.78 to -0.65; P = .014) and higher SPADI disability (MD = -28.01; 95% CI = -54.77 to -1.24; P = .040) and total scores (MD = -10.09; 95% CI = -16.85 to -3.33; P = .004) compared with the non-hemiplegic shoulder pain group. Pain intensity and duration showed no clinically meaningful differences. COPS further explained 54% of the variance in SPADI pain scores and 51.1% of the variance in SPADI total scores.

Individuals with PSSP demonstrated significantly higher pain centralizing behavior despite similar pain intensity and shorter pain duration compared with non-hemiplegic shoulder pain. Moreover, COPS scores explained a meaningful portion of pain and disability, highlighting the role of central mechanisms in PSSP.