## 4 Discussion  
Trunk control, which underpins postural stability and motor performance, is critical to sABI therapy. Balance, ambulation, and ADLs independence require a stable trunk. Patients with sABI generally have poor trunk control due to brain damage impacting sensory integration and movement coordination. Therefore, trunk strengthening and stabilization training is essential to rehabilitation programs because it improves posture, reduces fall risk, and promotes functional recovery. Data indicated that rehabilitation helped patients independently of their randomization group. Comparing the two groups, patients undergoing robotic trunk rehabilitation with hunova(r) showed significant improvements in trunk control and balance, as well as the  
Figure 2: Comparison of results from T0 and T1 between HuG and CoG in trunk control (TIS), motor performance (MI-LL AFF), autonomy (mBI), self-perceived quality of life (EQ-5D_VAS) and fatigue (MFIS). Improved TIS score (\(p\) = 0.013), MI-LL AFF score (\(p\) = 0.046), mBI score (\(p\) = 0.001) and EQ-5D_VAS (\(p\) = 0.011) are indicative of improved trunk control, motor performance with affected side, autonomy and quality of life. The decrease in MFIS physical score (\(p\) = 0.002) and MFIS total score (\(p\) = 0.017) is indicative of the improvement in the level of fatigue, especially motor fatigue. function of the most affected lower limb, autonomy, quality of life, and fatigue, particularly the motor component, confirming the literature data [47; 48; 49]. Regarding the instrumental assessment of static sitting balance, statistically significant improvements were found in COP area, COP path, and trunk movement only in patients undergoing experimental treatment. A worsening of some parameters was observed in the control group, but did not reach statistical significance. In particular, the control group showed an average increase in postural sway and trunk control. The difference between the two groups highlights the improvement of the experimental group compared to the control group. A similar situation occurs when analyzing the dynamic data: patients in the experimental group showed significant differences between T0 and T1 in COP area with both eyes open and closed, COP path, trunk movement, and COP range oscillation in the antero-posterior and mid-lateral directions. These individuals also slowed COP sway in all directions and circumstances, which are indicators of improved sitting balance and trunk movement in dynamic conditions. Patients in the control group, on the other hand, although not significantly, showed an increase in some parameters, indicative of worsening performance, which, however, did not reach statistical significance. Therefore, the comparison between the two groups shows a statistically significant improvement in sitting balance and trunk movement of the experimental group compared to the control group. As for stability limits, only in the experimental group did statistically significant differences emerge in sitting balance and trunk tilt. The comparison between the two groups showed a marked improvement in trunk tilt in favor of the experimental group. On the other hand, considering static balance with elevated seat, and thus with a reduction in the base of support, statistically significant differences emerged in the experimental group between T0 and T1 in some parameters indicating improvement in trunk control and sitting balance. This is indicative of stabilization despite the reduction in the base of support given the lack of ground contact of the lower limbs. Comparison between the groups showed a statistically significant improvement, especially in the quality of trunk movement: a reduction in sway corresponds to greater stability. The improvements recorded by the robotic platform could be due to the specific activity performed with humova(r) during the experiment.