Arm control recovery enhanced by error augmentation

Abstract

Here we present results where nineteen stroke survivors with chronic hemiparesis simultaneously employed the trio of patient, therapist, and machine. Massed practice combined with error augmentation, where haptic (robotic forces) and graphic (visual display) distortions are used to enhance the feedback of error, was compared to massed practice alone. The 6-week randomized crossover design involved approximately 60 minutes of daily treatment three times per week for two weeks, followed by one week of rest, and then repeated using the alternate treatment protocol. A therapist provided a visual target using a tracking device that moved a cursor in front of the patient, who was instructed to maintain the cursor on the target. The patient, therapist, technician-operator, and rater were blinded to treatment type. Several clinical measures gauged outcomes at the beginning and end of each 2-week period and one week post training. Results showed incremental benefit across most but not all days, abrupt gains in performance, and a benefit to error augmentation training in final evaluations. This application of interactive technology may be a compelling new method for enhancing a therapist's productivity in stroke-rehabilitation.

Figure 1-

Therapist(right), patient(left) demonstrating experimental set up

Figure 2-

Reaching movement contrasting performance before (left) and after (right) error-augmented treatment session. Colors represent reach towards low (red), medium (green) and high (blue) level targets.

Figure 3-

Reach value data grouped by condition (A), the 95% confidence intervals are shown as blue, green and grey bars. Individual data-points are overlaid. Fugl-Meyer scores are grouped and plotted with the same condition (B).