Effect of specialized task training of each hemisphere on interlimb transfer in individuals with hemiparesis

Therapeutic concept of interlimb transfer provides very important information relevant to patients with stroke because it can be applied to help these patients recover movement skills disrupted following unilateral damage to the brain.

The purpose of this study was to determine the transfer effects for both specialized training in each hemisphere and reversed training of a specialized task.

Twenty patients (ten women and ten men) with stroke and hemiparesis participated. All participants were in Brunnstrom recovery stage five or higher for arm and hand function and had Mini-Mental State Examination scores ≥25. We used a training task involving a modified static cone, modified box and block, and modified pegboard tasks. The specified-training group performed the reaching movements (based on grip, reach, and release movements) in a modified training setting in which left-handed participants began from a single starting location and proceeded to one of three target locations (1S3T condition), and the right-handed participants started form one of three starting locations and proceeded to a single target location (3S1T condition). The unspecified training group performed these movements starting under reverse-start and target conditions.

As a result of the left-to-right limb transfer in the specified-training group differed significantly in duration from that in the pre-training group. Also, the biceps brachii and triceps (lateral head) muscles were significantly more active after performing the specified training than before. On the other hand, the activity of the upper trapezius muscle did not significantly differ after specified training compared with before training.

Consequently, a symmetric transfer advantage was observed that depended on the characteristic resources of each hemisphere. The transfer of specified training from one arm to the other had a more positive influence on functional recovery than did unspecified training for patients with stroke and hemiparesis.