Somatosensory impairments are common after stroke but have only a small impact on post-stroke shoulder pain

OBJECTIVE: To investigate whether somatosensory impairments are more common in individuals with post-stroke shoulder pain than in those without post-stroke shoulder pain and healthy controls. DESIGN: Descriptive analysis of a convenience sample. PARTICIPANTS: Forty-nine individuals with stroke, 24 with and 25 without post-stroke shoulder pain (median age 65 years), and 11 age- and sex-matched healthy controls. METHODS: Perception and pain thresholds for cold, warm and heat (thermal thresholds), and pain thresholds for pressure and pin prick (mechanical thresholds) were assessed using quantitative sensory testing (QST). Passive range of motion, motor function, resistance to passive movements, light touch and proprioception were assessed in the upper extremities. Shoulder pain characteristics were recorded in the post-stroke shoulder pain group. RESULTS: There were no significant differences between the group with post-stroke shoulder pain and the group without post-stroke shoulder pain in any of the QST assessments, but more participants in the post-stroke shoulder pain group reported abnormal cold sensation in the affected side. Both stroke groups had generally higher thermal thresholds and more extreme low or high mechanical thresholds than the healthy controls. CONCLUSION: Somatosensory impairments are common among individuals with stroke compared with healthy controls. The non-significant differences in QST thresholds between the group with post-stroke shoulder pain and the group without post-stroke shoulder pain indicate that somatosensory impairments have only a small impact on post-stroke shoulder pain.