## 4 Discussion  
This study aimed to investigate the effect of group therapy and an MIT interactive system program to enhance gait function of chronic stroke patients, and to compare the clinical contribution of CI and BBS index in measuring postural stability. This is the first study of the direct application of MITs to stroke patients with hemiparesis. Based on the medical ethics and IRB requirements of clinical intervention experiments, it is not easy to collect a large number of research subjects for stroke-related intervention studies, and the first study for comparison of the CI of MMSE values and BBS score for the participating in clinical application. Despite the small drawback of its ceiling effect, the BBS is one of the most commonly applied clinical measures of balance for individuals with stroke. Based on their previous clinical experiences, the developers of the BBS proposed that scores below 45 (out of 56) indicate an increased risk for falls [36; 37]. In this study, after 12 weeks of training, the mean BBS score of the study participants was increased from 51.67 to 53.83, with an average improvement of 4.2%. Moreover, the results showed a statistically significant difference between pre- and post-test scores (\(p<0.05\)). The study results thus showed that the 12-week exercise program including MIT training should improve the postural stability of these chronic stroke patients and provided value in rehabilitation therapy. However, due to the sampling method and lack of a control group, further research is required. The results were similar to those reported in the study [17] focused on healthy elderly in the community. Using MITs for gameplay and interactive training activities can improve the balance, mobility, agility, etc. of those using the MITs and reduce the incidence of falls. Traditional (conventional) group exercises for chronic stroke patients in the hospital rehabilitation treatment center only include strength training and balance exercise training, and such exercises are unable to achieve effective two-way feedback. These single approach and low-variability training activities also result in reduced patient participation. MIT training, in contrast, provides VR feedback in the form of games that effectively improves patient motivation. The purpose of this study was to increase motivation and achieve two-way feedback on the MIT exercise program. This aimed to increase patient interest and compliance, prolong movement time, reduce the difficulty of upper limb support to increase the difficulty of the movement, and promote muscle strength, movement coordination, and postural stability. These are very important for chronic stroke patients and even healthy elderly people. In this study, the difference in the mean BBS pre- and post-test scores was small but statistically significant (\(p=0.0313\)). However, the degree of improvement was only 4.2%, lower than the improvement in the CI results (14.8%) based on the COP measurement MMSE method. Among all 9 subjects, four subjects achieved the full BBS score (56). This finding could be explained by a ceiling effect of the BBS, with a ceiling effect occurring when a significant proportion of a tested population achieves the highest possible score on a test [38; 39]. On the other hand, according to the results of a study by [PERSON] et al. [40], there was misfit for two of the 14 BBS items of the BBS (specifically, the tandem standing and standing on a single foot items). According to the original instructions for the BBS, the individual taking the test can decide which limb to utilize for the tandem stance and the single-limb stance items. However, administering these items in a standardized manner could potentially enhance the effectiveness of the BBS in terms of accurately measuring an initial balance impairment, as well as changes to a person's balance caused by