Electrical stimulation-based paradigm to enhance lower limb motor imagery: initial validation in stroke patients

Lower limb motor dysfunction is a prevalent complication of stroke that significantly impacts patients' quality of life. Current research indicates that motor imagery-based brain-computer interface (BCI-MI) training can assist stroke patients in enhancing motor function and reconstructing neural pathways. Nevertheless, 40% of stroke patients struggle with effective motor imagery (MI), leading to challenges in applying lower limb MI in clinical settings. Electrical stimulation (ES) has demonstrated the ability to induce muscle contractions, generating a kinesthetic illusion that effectively guides subjects in performing MI. However, the existing study lacks clarity regarding the effectiveness of the ES-MI paradigm in improving lower limb MI in stroke patients. To address this gap, we recruited seven stroke patients to participate in an experiment involving the ES-MI enhancement paradigm, aiming to validate its performance in stroke patients. The results revealed that the ES-MI paradigm augmented the activation of the motor cortex in the lower limb and reactivated dormant areas, suggesting that MI training based on the ES-MI paradigm holds promise for enhancing neural remodeling effects in stroke patients. Additionally, the paradigm enhanced the classification accuracy of SVM(+1.17%), KNN(+0.93%), RF(+7.13%), LDA(+5.29%), and EEGNet(+0.96%), indicating potential improvements in the efficiency and quality of human-robot interaction in brain-controlled lower limb rehabilitation robots.