Parkinson's disease (PD) is a neurodegenerative disease of the central nervous system. Although PD is commonly characterized by well-known clinical manifestations, it also involves imbalances in the cortico-subcortical excitation and inhibition processes. Functional electrical stimulation can improve the motor condition of PD patients as a supplement to levodopa therapy. In this study, clinical (using specific tests) and paraclinical (using single-pulse transcranial magnetic stimulation) examinations revealed an improvement in the motor symptoms and the bilateral activation of the primary motor areas of the upper limbs after unilateral functional electrical stimulation in PD patients.