Motor imaging therapy is of great significance to the rehabilitation of patients with stroke or motor dysfunction, but there are few studies on lower limb motor imagination. When electrical stimulation is applied to the posterior tibial nerve of the ankle, the steady-state somatosensory evoked potentials (SSSEP) can be induced at the electrical stimulation frequency. In order to better realize the classification of lower extremity motor imagination, improve the classification effect, and enrich the instruction set of lower extremity motor imagination, this paper designs two experimental paradigms: Motor imaging (MI) paradigm and Hybrid paradigm. The Hybrid paradigm contains electrical stimulation assistance. Ten healthy college students were recruited to complete the unilateral movement imagination task of left and right foot in two paradigms. Through time-frequency analysis and classification accuracy analysis, it is found that compared with MI paradigm, Hybrid paradigm could get obvious SSSEP and ERD features. The average classification accuracy of subjects in the Hybrid paradigm was 78.61%, which was obviously higher than the MI paradigm. It proves that electrical stimulation has a positive role in promoting the classification training of lower limb motor imagination.
运动想象疗法对中风或运动功能障碍患者的康复训练具有重要意义，但针对下肢运动想象的研究较少。当对脚踝胫后神经施加电刺激时，在电刺激频率处可诱发出稳态体感诱发电位（SSSEP）。为了更好地实现下肢运动想象的分类，提高分类效果，丰富下肢运动想象的指令集，本文设计了两种实验范式：运动想象（MI）范式和有电刺激辅助的混合（Hybrid）范式，并招募了 10 名身体健康的大学生在两种范式中完成左、右脚单侧运动想象任务。通过时频分析和分类准确率分析发现，相比 MI 范式，Hybrid 范式下可得到明显的 SSSEP 和 ERD 特征，受试者在 Hybrid 范式中平均分类准确率为 78.61%，较 MI 范式显著提高，证明电刺激辅助在下肢运动想象分类训练中有积极的促进作用。.
Keywords: electrical stimulation assistance; event-related desynchronization; lower limbs motor imagery; steady-state somatosensory evoked potentials.