When does spasticity in the upper limb develop after a first stroke? A nationwide observational study on 861 stroke patients.

This study investigated the time taken for upper extremity spasticity to develop and its regional difference after first-ever stroke onset in a nationwide multicenter study in South Korea. The retrospective observational study included 861 individuals with post-stroke spasticity in the upper limbs. Spasticity in the upper extremity joints was defined as a modified Ashworth Scale score ≥1. The median time to develop upper limb spasticity after stroke onset was 34 days. 12% of post-stroke spasticity cases developed between 2 months and 3 months and 13% developed after 3 months from onset. At the time of diagnosis of spasticity, most patients showed only a slight increase in muscle tone, which was observed most frequently in the elbow, followed by the wrist, and fingers. Younger stroke survivors were more spastic, and the severity of spasticity increased with time. Approximately half of the patients with post-stroke spasticity developed spasticity during the first month. However, post-stroke spasticity can develop more than 3 months after stroke onset. Therefore, it is important to assess spasticity, even in the chronic state.