Preliminary investigation of an electromyography-controlled video game as a home program for persons in the chronic phase of stroke recovery

Abstract

Objective: To investigate the preliminary effectiveness of surface electromyography (sEMG) biofeedback delivered via interaction with a commercial computer game to improve motor control in chronic stroke survivors.

Design: Single-blinded, 1-group, repeated-measures design: A1, A2, B, A3 (A, assessment; B, intervention).

Setting: Laboratory and participants' homes.

Participants: A convenience sample of persons (N=9) between 40 and 75 years of age with moderate to severe upper extremity motor impairment and at least 6 months poststroke completed the study.

Intervention: The electromyography-controlled video game system targeted the wrist muscle activation with the goal of increasing selective muscle activation. Participants received several laboratory training sessions with the system and then were instructed to use the system at home for 45 minutes, 5 times per week for the following 4 weeks.

Main outcome measures: Primary outcome measures included duration of system use, sEMG during home play, and pre/post sEMG measures during active wrist motion. Secondary outcomes included kinematic analysis of movement and functional outcomes, including the Wolf Motor Function Test and the Chedoke Arm and Hand Activity Inventory-9.

Results: One third of participants completed or exceeded the recommended amount of system use. Statistically significant changes were observed on both game play and pre/post sEMG outcomes. Limited carryover, however, was observed on kinematic or functional outcomes.

Conclusions: This preliminary investigation indicates that use of the electromyography-controlled video game impacts muscle activation. Limited changes in kinematic and activity level outcomes, however, suggest that the intervention may benefit from the inclusion of a functional activity component.

Keywords: Rehabilitation; Stroke; Technology; Telemedicine; Video games.

Figure 1

Example EMG from the agonist extensor muscle (EDC, black traces) and antagonist flexor (FCR-grey traces) during the reach task. The co-contraction ratio is calculated by comparing the relative integrated area under the rectified EMG of each muscle, during the time of the agonist activity. During the period of the reach movement determined from video records (not shown), the agonist muscle onset and offset (vertical lines) are detected when activity crosses a threshold of 5SD above baseline activity (shown in A). The ratio of the resulting cumulative integrals of each muscle (shown in B) is the co-contraction value.

Figure 2

The number of hours of game play across the four week intervention for each subject. Subjects are ordered by the amount of time they chose to participate in the NGT intervention in the home. Additional game therapy as part of training was performed in the laboratory prior to using the system in the home for each subject.

Figure 3

Independent activity across game play sessions. Subjects are ordered by the number of hours of game play suitable for analysis including training and home play. Of subjects that played 10 or more hours (dashed line), five of six subjects improved muscle independence based on a significant (* p<0.05) positive regression between independence and game play session.

Figure 4

Maximal voluntary contraction (MVC) during pre-game calibration plotted across game play sessions. Subjects are ordered by the number of hours of game play suitable for analysis including training and home play. Six of nine subjects improved muscle activation of at least the extensor (top row) or flexor (bottom row) muscles based on a significant (* p<0.05) positive regression between muscle activity and game play session, while four of these subjects improved activation of both muscles. Note that three subjects improved EMG greater than 300%, requiring greater range on the abscissa, and select axes are thus marked with green text to highlight this difference.