Validity and reliability of the chronic composite XA, an upper limb motor assessment using Active Range of Motion in patients with chronic stroke.

Only 28 patients were analysed, and they were selected from a larger trial's screening and baseline data, so the sample was small and the extended shoulder and forearm model was exploratory. The participants were narrow: chronic stroke over 6 months after a first unilateral supratentorial stroke, with moderate upper limb paresis and FMA-UE scores between 22 and 53 out of 66, so results may not apply to acute or subacute stroke or to very mild or very severe impairment. Only one assessor evaluated participants at both visits, so inter-rater reliability was not assessed. The time between visits varied from two to eight weeks, although participants were assumed to be stable because they were in the chronic phase. Responsiveness and minimal clinically important difference were not tested, so the MDC shows measurement noise rather than what change matters to patients. The expanded score had a larger SEM and MDC than the initial CX A, and grip strength correlated only weakly with CX A.

The authors declared no financial conflicts of interest. The study was funded by La Fondation pour la Recherche sur les AVC and l'Institut de Neurosciences Cliniques de Rennes.

Do not read this as evidence that a treatment improves arm function. The paper validates a measurement score in 28 chronic stroke patients with moderate arm paresis, and a total CX A gain above 64 degrees is needed before calling a change clinically significant.