Acceleration metrics are responsive to change in upper extremity function of stroke survivors

Objectives: To (1) determine whether acceleration metrics derived from monitoring outside of treatment are responsive to change in upper extremity (UE) function; and secondarily to (2) compare metric values during task-specific training and while in the free-living environment, and (3) establish metric associations with an in-clinic measure of movement capabilities.

Design: Before-after observational study.

Setting: Inpatient hospital (primary purpose); outpatient hospital (secondary purpose).

Participants: Individuals (n=8) with UE hemiparesis <30 days poststroke (primary purpose); individuals (n=27) with UE hemiparesis ≥6 months poststroke (secondary purpose).

Intervention: The inpatient sample was evaluated for UE movement capabilities and monitored with wrist-worn accelerometers for 22 hours outside of treatment before and after multiple sessions of task-specific training. The outpatient sample was evaluated for UE movement capabilities and monitored during a single session of task-specific training and the subsequent 22 hours outside clinical settings.

Main outcome measures: Action Research Arm Test (ARAT) and acceleration metrics quantified from accelerometer recordings.

Results: Five metrics improved in the inpatient sample, along with UE function as measured on the ARAT: use ratio, magnitude ratio, variation ratio, median paretic UE acceleration magnitude, and paretic UE acceleration variability. Metric values were greater during task-specific training than in the free-living environment, and each metric was strongly associated with ARAT score.

Conclusions: Multiple metrics that characterize different aspects of UE movement are responsive to change in function. Metric values are different during training than in the free-living environment, providing further evidence that what the paretic UE does in the clinic may not generalize to what it does in everyday life.