Development of Knee Control Training System Using Virtual Reality for Hemiplegic Patients and Feasibility Experiment with Normal Participants

Patients with hemiplegia have an asymmetric gait symptom due to a hemiplegic paralysis. Hip, knee, angle joint angle are measured for suitable gait training of hemiplegic gait disorder. Measured angles are used to grasp the difference between normal and abnormal sides. In particular, knee joint is more important than the other joints to hemiplegic patients. So, we developed marker based knee angle measurement system which is able to measure angle of knee joint using PC and PC camera. Then we integrated VR rehabilitation training system with the marker based knee angle measurement system. VR tasks were constructed with crossing stepping-stones to practice knee flexion and extension during walking. To validate feasibility of VR system, we performed experiment using a treadmill with a speed of 2.0 km/h and various target angles (40 degree, 50 degree, and 70 degree). The purpose of this study ascertained that normal participants make a success of task with the usual target angle (50 degree) as well as the unusual target angle (40 and 70 degree). Four healthy males (age from 24 to 28 years) were recruited for this experiment. And we measured average of trial numbers for success in each period. Training periods divided into the first stage, middle stage, and last stage for the analysis. In the result of trial number to succeed each task, trial number at 50 and 70 degrees showed a tendency of decrease. Questionnaire result represents that gain positive rate in performing knee control task using VR. In conclusion we ascertained that VR system help with gradually increasing control ability of knee joint of the participants at 50 and 70 degrees. Also, we expect that the developed VR rehabilitation training for knee control could be possible to use for practical gait training for patients with hemiplegia if they will felt such as normal.