Deficient Pain Modulation in Patients with Chronic Hemiplegic Shoulder Pain.

Background: Hemiplegic shoulder pain (HSP) following stroke significantly affects the individual's function and quality of life. The mechanism of HSP is not clearly understood; hence, it is unclear why HSP resolves spontaneously or following routine care in some patients, while in others it becomes persistent. The aim was therefore to study whether HSP is associated with deficient pain modulation.