We developed a new and innovative TS-VR training program for the hemiparetic hand after stroke. The main finding of this study was the demonstration of statistically significant improvements in upper-extremity functional movements of patients with hemiparetic stroke after a two-week TS-VR training program. There was statistically significant enhancement in both quality and quantity of the performance of the affected hand during the daily functions of patients. The results of FMA-UE Total, FMA-UL, FMA-Hand, WFMT, MAL-AOU, and MAL-QOM showed significant improvement within groups across the outcome measures among the three measurement occasions. The TS-VR was proved to be useful for training patients’ hand function after stroke.
Our study found that the higher-functioning group benefited more from the TS-VR, as indicated in outcome measures of FMA-UL, FMA-Hand, FMA-UE Total, and WMFT respectively, as well as AOU score in MAL. Compared with the higher-functioning group, patients in the lower-functioning group only participated in certain lower levels with limited use of distal joints and muscles with lower speed, whereas patients in the higher-functioning group could perform a greater variety of movements, with the involvement of greater use of different joints and muscles in upper extremity from proximal to distal, especially hand and isolated finger movement. Moreover, the nature of our TS-VR training is duration-fixed (30 minutes) but not repetitive or interval-fixed. Patients in the higher-functioning group were able to perform higher repetitions because of their faster rate of performance. This result highlights the significance of the design and nature of TS-VR training in achieving differential benefits to stroke patients with various levels of arm severity. Further research on training duration, repetition, and frequency of the TS-VR program would bring out significance differences in the benefits for higher- and lower- functioning groups.
The significant increase in MAL-QOM score after TS-VR training in the higher-functioning group but not in the lower-functioning group could possibly be explained by their different functional levels. Following completion of the TS-VR program, the overall upper extremity function increased in both groups. However, in the lower-functioning group, the improvement might only be seen in the proximal joint movement (i.e., increased shoulder flexion, external rotation, and elbow extension). The improvements were insufficient for hand functions in the MAL questionnaire, like holding a cup, opening a drawer, or eating with a spoon., Hence, the overall quality of movement in these tasks remained similar after the TS-VR program. The grip strength of both groups showed no significant improvement after the course of TS-VR training. This is understandable as the TS-VR training did not include any strengthening element in any of its levels but only movement control and range of motion.
One of the reasons for the significant improvements after TS-VR training might be attributed to training with high frequency and appropriate intensity. Our treatment program consisted of a total of 10 sessions, each lasting 30 minutes, held five days per week over two consecutive weeks. Previous research has revealed that the intensity of task-specific trainings need not necessarily be high in order to achieve optimal effects. Training sessions that are as short as 15 minutes have resulted in lasting changes in cortical representation . Our findings are consistent with those from numerous previous studies [5–7], which have suggested that less intense (i.e., 30–45 minutes) task-specific training regimens can lead to significant improvements in the use and functions of the affected limb.
We conducted our training on a one-to-one basis with supervised therapy. During each supervised session, the facilitator selected activities that were suitable to the functional level of the patients and determined the repetitions of activities to be performed. Moreover, the facilitator provided specific and ongoing verbal and tactile cues on participants’ performance. This extrinsic and instant feedback on movement quality can effectively correct patients’ unwanted or compensatory movement patterns, which is also a key principle in skill acquisition . In addition, the 3D and graphically ‘enriched’ environments with multimodal feedback (visual, auditory, tactile) in VR settings also provided sensory input to the patients, which made them more motivated to attend the training than they would have been to attend conventional training, which is less playful and interactive.
It might also be possible to explain improvements in MAL as resulting from one of the unique features of our VR training program, that is, it’s adoption of task-specificity in a progressive manner. In order to be ‘task specific’, each action in the training tasks must specify an object to reach for. The tasks are simulating conditions in real life in order to enhance carry-over into daily life activities (Cunningham et al., 2016). Our TS-VR program is composed of seven functional tasks according to seven ordered levels of increasing complexity. The complexity of the tasks is related to the Brunnstrom theory of development of the hemiparetic upper limb in recovery, with reference to the respective key actions corresponding to levels 1–7 in the FTHUE [21, 22, 30, 31]. Our study, to our knowledge, is the first one incorporating task-specificity with increasing levels of complexity into VR training for the hemiparetic upper extremity. The results may be useful as supporting evidence for integrating task-specificity and virtual reality into programs for the treatment of upper limb motor impairments during stroke rehabilitation.
In our study, we attempted to explore the effectiveness of TS-VR rehabilitation that focused on the distal upper extremity up to the forearm, using the LMC as an input device. The advantage of the LMC is that it is cheap and easily set up, requiring only a desktop computer or laptop, the LMC, and our TS-VR training program. There are also existing studies focused more on proximal upper limb rehabilitation . Kinect, which is a widely commercially available motion sensing device, recognizes the body’s joint positions, especially for proximal joints like shoulder and elbow. However, VR systems like Kinect do not benefit the distal joints, which are important in hand function training such as grasp and release. To address this limitation, we used the LMC in our TS-VR program, as this motion sensor is able to capture the motion of wrist and of each of the finger joints, enabling it to accurately measure fine motor movements . To further develop our TS-VR program in the future, we suggest combining the use of Kinect and the LMC, as there are currently no VR systems involving both proximal and distal upper extremity movements at the same time . Further research to explore the effectiveness of the combined use of devices that can measure both gross motor and fine motor abilities would be useful is recommended as a direction for future investigations.