The Fundamental Mechanism of Transcranial Electrical Stimulation in Post-Stroke Rehabilitation

Stroke is a leading cause of long-term disability, and many patients fail to achieve complete recovery following cerebral injury. Therefore, post-stroke rehabilitation is essential to restore impaired function. Transcranial electrical stimulation (tES), transcranial direct current stimulation (tDCS), and transcranial alternating current stimulation (tACS) have emerged as promising neuromodulation approaches to enhance post-stroke recovery. These treatments have therapeutic effects to restore impaired function by modulating cortical excitability and reorganizing brain tissue through electrical stimulation. However, the fundamental mechanisms underlying these therapeutic effects remain poorly understood. This review focused on the neurobiological mechanisms underlying tES that extend beyond cortical excitability and encompass long-term neuroplasticity, cerebral blood flow, neurometabolism, and neuroinflammatory modulation. Our summary provides a comprehensive understanding of tES processes and plays a vital role in the advancement of improved treatments. Additionally, our review promotes enhanced clinical outcomes through interactions with various stroke rehabilitation strategies.