Validity of Accelerometry for Monitoring Real-World Arm Activity in Patients With Subacute Stroke: Evidence From the Extremity Constraint-Induced Therapy Evaluation Trial

Uswatte G, Giuliani C, Winstein C, Zeringue A, Hobbs L, Wolf SL. Validity of accelerometry for monitoring real-world arm activity in patients with subacute stroke: evidence from the Extremity Constraint-Induced Therapy Evaluation trial.ObjectiveTo examine the psychometric properties of an objective method for assessing real-world arm activity in a large sample with subacute stroke.DesignValidation study.SettingCommunity.ParticipantsPersons 3 to 9 months poststroke (N=169) with mild to moderate motor impairment of their hemiparetic arm enrolled in a multisite, randomized clinical trial of constraint-induced movement therapy.InterventionsNot applicable.Main Outcome MeasuresParticipants wore an accelerometer on each arm outside the laboratory for 3 days before and after treatment or an equivalent no-treatment period. They also completed the Actual Amount of Use Test (AAUT), which is an observational measure of spontaneous more-impaired arm use, and the Motor Activity Log (MAL), which is an interview assessing more-impaired arm use in daily life.ResultsLow-pass–filtered accelerometer recordings were reliable (r range, >.8) and stable (P range, >.48). Their validity was also supported. Correlations calculated across all participants at baseline between the ratio of more-impaired to less-impaired arm accelerometer recordings and AAUT and MAL scores were .60 and .52, respectively.ConclusionsAccelerometry provides an objective, real-world index of more-impaired arm activity with good psychometric properties.