Responsiveness, Minimal Clinically Important Difference, and Predictive Validity of the ArmCAM in Stroke Rehabilitation: A Remotely Delivered Upper Extremity Function Assessment

Objective: The Arm Capacity and Movement Test (ArmCAM) is a remotely delivered measure for evaluating upper extremity motor function poststroke. This study examined the responsiveness, minimal clinically important difference (MCID), and predictive validity of the ArmCAM in individuals with stroke undergoing rehabilitation therapy. Design: Secondary analysis of a multisite randomized controlled trial. Setting: Participants’ homes. Participants: Sixty-two individuals with stroke (mean age=62.7 years, 32.3% women, mean time poststroke=221.9 days). Interventions: A 3-week virtually delivered upper extremity exercise program. Main Outcome Measures: The ArmCAM, the Rating of Everyday Arm-use in the Community and Home (REACH) Scale, and the Stroke Impact Scale (SIS) were administered remotely via videoconferencing. These assessments were conducted before and after the intervention. The standardized response mean (SRM) was calculated for responsiveness. Anchor- and distribution-based methods were used to estimate the MCID. Predictive validity was assessed using the Spearman correlation coefficient (ρ). Results: ArmCAM demonstrated high responsiveness to changes in upper extremity motor function after the intervention (SRM=0.92). The anchor-based MCID estimates were 3.3, 2.5, and 2.7 for the REACH Scale, the SIS Hand Function Domain, and the SIS Recovery Score, respectively. The distribution-based MCID estimate was 3.2. Baseline ArmCAM scores showed moderate predictive validity for posttest scores on the REACH Scale (ρ=0.61) and in the SIS Hand Function Domain (ρ=0.59), and fair predictive validity for SIS Recovery Scores (ρ=0.44). Conclusions: The findings support the use of ArmCAM as a responsive and predictive remote assessment tool for evaluating upper extremity motor function poststroke. Its MCID estimates provide essential information for evaluating clinical benefits. ArmCAM is recommended for use in telerehabilitation contexts. © 2026 American Congress of Rehabilitation Medicine