[Purpose] The purpose of this study was to determine whether two-handed task training is effective on motor learning of injured cerebral cortex activation and upper extremity function recovery after stroke.
[Subjects and Methods] Two hemiplegic subjects participated in this study: one patient was affected on the dominant side of the body and the other was affected on the non-dominant side of the body, and both scored in the range of 58–66 in the Fugl-Meyer assessment. The excitability of the corticospinal tract and Manual Function Test were examined.
[Results] The excitability of the corticospinal tract and the Manual Function Test showed significant differences in the activation of both sides of the cerebral cortex and in the variation in learning effect of upper extremity motor function recovery in patients with hemiplegic non-dominant hand (left).
[Conclusion] The results suggested that two-handed task training had a different influence on dominant hand (right) and non-dominant hand (left) motor recovery.
The dominant hand is defined as the hand that is usually used in performing activities of daily living (ADL). The development of the motor function of the cerebral cortex is asymmetrical to the dominant hand1) . Based on such asymmetrical development of the cerebral cortex, when the left hand is performing a task, the cerebral cortex motor area of the right cerebral hemisphere activates. However, a more interesting fact is that when the right hand is used functionally, the nerve cells of the entire cerebral cortex motor area of the right and left cerebral hemispheres activate2) . This finding supports the evidence of lateralization of the cerebral hemisphere and implies that the left cerebral hemisphere acts the role of the dominant cerebral hemisphere when performing ADL2, 3) . Thus, the left hemisphere, which is the dominant cerebral hemisphere due to the lateralization of the cerebral hemisphere, is more closely related with motor planning in ADL performance, and the same relationships were shown after cerebral hemisphere injury due to stroke3, 4) . Characteristically, the patient with stroke-damaged dominant left cerebral hemisphere reports a time delay on the exercise performance of both right and left hands, whereas the patient with damaged right cerebral hemisphere reports a mild motor function disorder confined to the left hand3) . This means that, consequently, after stroke onset, the patient with hemiplegic dominant hand (right) experiences more difficulty in performing ADL5) . However, regarding upper extremity rehabilitation, there is no study that differentiated the motor function recovery of the upper extremity of patients who are affected in the dominant cerebral hemisphere (with the hemiplegic right hand) or in the non-dominant cerebral hemisphere (with the hemiplegic left hand). A specific rehabilitation approach based on laterality through classification of cerebral damage on the right or left side is needed to achieve a more successful rehabilitation of the upper extremity. Thus, the purpose of this study is to determine whether two-handed task training is effective in the motor learning of the injured cerebral cortex activation and upper extremity function recovery after stroke.