Mental practice effect on line-tracing accuracy in persons with hemiparetic stroke: A preliminary study

Objective: To investigate the effect of mental practice on line-tracing accuracy of persons with hemiparetic stroke. Design: A single-case, experimental, multiple baseline design. Setting: Electromyography laboratory of a rehabilitation medicine department of a university hospital. Participants: Three persons with right hemiparesis from stroke. Intervention: Mental practice for line-tracing training. Main Outcomes Measures: Two tracing tasks were used to evaluate the effect of mental practice: (1) tracing a 5.9-inch long horizontal line (task 1); and (2) tracing a 6-inch long curved line (task 2) as a generalization probe. Participants were first trained to master the cognitive rehearsal skill by checking the reduction level of tension in their upper trapezius while listening to a relaxation cassette tape. Second, participants were trained to trace task 1 immediately after listening to a cognitive rehearsal tape that contained the command to trace over a horizontal line as accurately as possible. Then, without the cognitive rehearsal process, participants traced over a curved line as a generalization probe. The dependent variable, called the line length error, was the total distance that the traced line deviated from the printed lines (both horizontal and curved). Results: Mean-line length errors of participants 1, 2, and 3 were: horizontal line tracing, 3.33, 7.38, and .30 inches, respectively, in the baseline and 1.41, 2.70, and .24 inches, respectively, after mental practice training. With the curved line tracing, mean length errors were 3.15, 6.56, and .52 inches in the baseline and 1.85, 4.36, and .80 inches postintervention, respectively. Conclusions: Mental practice can be an effective method to improve line tracing by persons with hemiparetic stroke. Training in horizontal line tracing showed a modest level of generalization to curved line tracing.