Error-augmented bimanual therapy for stroke survivors

Abstract

Background: Stroke recovery studies have shown the efficacy of bimanual training on upper limb functional recovery and others have shown the efficacy of feedback technology that augments error.

Objective: In a double-blinded randomized controlled study (N = 26), we evaluated the short-term effects of bilateral arm training to foster functional recovery of a hemiparetic arm, with half of our subjects unknowingly also receiving error augmentation (where errors were visually and haptically enhanced by a robot).

Methods: Twenty-six individuals with chronic stroke were randomly assigned to practice an equivalent amount of bimanual reaching either with or without error augmentation. Participants were instructed to coordinate both arms while reaching to two targets (one for each arm) in three 45-minute treatments per week for two weeks, with a follow-up visit after one week without treatment.

Results: Subjects' 2-week gains in Fugl-Meyer score averaged 2.92, and we also observed improvements Wolf Motor Functional Ability Scale average 0.21, and Motor Activity Log of 0.58 for quantity and 0.63 for quality of life scores. The extra benefit of error augmentation over the three weeks became apparent in Fugl-Meyer score only after removing an outlier from consideration.

Conclusions: This modest advantage of error augmentation was detectable over a short interval encouraging further research in interactive self-rehabilitation systems that can enhance error motor recovery.

Keywords: Stroke; bimanual coordination; error augmentation; robotics rehabilitation; self-rehabilitation; upper extremity.

Fig. 1.

Participant recruitment flow diagram, based on followed the CONSORT protocols.

Fig. 2.

Experimental setup; Robot handle is attached to participant’s affected hand and a position tracker is attached to the other arm. Two red cursors each represent one of the participant’s hands position, and the target pairs are shown in yellow.

Fig. 3.

Study (top), session layout (bottom).

Fig. 4.

Clinical score changes from the first visit, AMFM score (A), WMFT score (B), MAL quantity (C) and MAL quality (D). Solid line shows the EA treatment (red), the non-EA treatment (dark blue) and the non-EA treatment without the outlier data (light blue) and dashed lines are the periods without treatment.

Fig. 5.

Intrinsic Motivation Inventory results, each tick mark shows response of a subject, different categories are shown in various colors.