4. Discussion
lower limb dysfunction, subacute stroke, stroke, subacute stroke lower limb disorders
STROKE, SECONDARY, STILL, CORTEX
In this study, ctDCS combined with CGR (trial group) was compared with sham-tDCS combined with CGR (control group). The wearable gait analyzer was used to standardize the analysis of patients' lower limb gait function. The results showed that the trial group performed significantly better than the control group in lower limb motor function (FMA-LE) at posttreatment T1 and follow-up assessment T2. This suggests that ctDCS plus CGR is an effective method to improve the motor synergy, reflex, and coordination function of the lower limbs in patients with subacute stroke. Furthermore, in terms of the secondary outcomes, the effects of the trial group were superior in the control group except for the 10MWT outcome at T2, and the patients improved balance, increased walking ability, and reduced the risk of falls.The mechanism of the efficacy of tDCS in lower limb dysfunction after stroke may explain our results to some extent. The current mechanism is still unclear, and the main consideration is based on the following mechanisms: the interhemispheric inhibition (IHI) theory [The ctDCS reduces the excitability of the cerebral cortex, downregulating the contralateral inhibitory pathway on inhibition of the ipsilateral hemisphere, increasing the interhemispheric connectivity of specific brain regions to play a crucial role, and thus improving motor function of the lower limb [Moreover, as lower limb motor function improved, the outcome of IADL was better in the trial group than in the control group, improving the patient's life independence and the possibility of returning to work and society. However, improved lower limb motor function was not associated with decreased HAMD levels, improved pessimism, and increased motivation, while recent studies have shown that recovery of stroke function is positively associated with mood [This is a limited pilot study. To some certain extent, it provides reference and guidance for rehabilitating patients with subacute stroke lower limb disorders in clinical practice. Still, it should be emphasized that the strength of our conclusions is limited. First of all, the sample size was small. The number of enrolled patients may have hindered assessing the effect of cathodal tDCS treatment, so our study can be considered a pilot. To further confirm our findings, randomized controlled trials involving larger subject populations are needed. Secondly, tDCS has no optimal parameters at present, including electrode placement, intensity, and timing relative to rehabilitation interventions, as well as patient characteristics which are limited in the previous studies [