Effect and mechanism of mirror therapy on lower limb rehabilitation after ischemic stroke: A fMRI study

BACKGROUND: Mirror therapy has been gradually adopted for lower limb rehabilitation, but its efficacy and neural mechanism are not well understood. OBJECTIVE: This study aims to investigate the effect and neural mechanism of mirror therapy on lower limb rehabilitation after ischemic stroke by using resting state functional magnetic resonance imaging (rs-fMRI). METHODS:A single-blind and randomized controlled pilot study was conducted. 32 patients with ischemic stroke were included in this study and randomly divided into two groups - the control group (CT, n = 16) and the mirror therapy group (MT, n = 16). Both the CT and MT groups received medication and routine rehabilitation training. In addition, mirror therapy was added to the MT group 5 times a week for 30 minutes each time over a period of 3 weeks. Patients' motor functions, functional connectivity (FC), regional homogeneity (ReHo), and fractional amplitude of low-frequency fluctuations (fALFF) were analyzed both before and immediately after the treatment. RESULTS: Patients' motor functions showed significant improvement in both groups compared to those before treatment (p < 0.01). Moreover, the MT group showed significantly better improvement than the CT group after the treatment (p < 0.05). FC, ReHoand fALFF indicated enhanced neuronal activities in motor function-related brain regions in the MT group compared to the CT group. CONCLUSION: Mirror therapy promotes the recovery of lower limb motor functions in patients with ischemic stroke. Through the comparative rs-fMRI analysis, it is found that the mirror therapy promotes the functional reorganization of the injured brain.