1. Introduction
movement sensations, post-stroke, Stroke, neuromuscular disability, lower-limb impairments, sudden loss of focal neurological function, stroke, urban mobility, visual motor imagery, hemorrhage, neurological diseases, neuromuscular disabilities, kinesthetic motor imagery, MP, infarction
NEUROLOGICAL DISEASE, STROKE, STROKE, EVENT, DISORDERS, HEMORRHAGE, INFARCTION, CORTEX, BRAIN INFARCTION
Stroke is a debilitating clinical condition resulting from a brain infarction or hemorrhage that poses significant challenges for motor function restoration. Previous studies have shown the potential of applying transcranial direct current stimulation (tDCS) to improve neuroplasticity in patients with neurological diseases or disorders. By modulating the cortical excitability, tDCS can enhance the effects of conventional therapies. While upper-limb recovery has been extensively studied, research on lower limbs is still limited, despite their important role in locomotion, independence, and good quality of life. As the life and social costs due to neuromuscular disability are significant, the relatively low cost, safety, and portability of tDCS devices, combined with low-cost robotic systems, can optimize therapy and reduce rehabilitation costs, increasing access to cutting-edge technologies for neuromuscular rehabilitation. This study explores a novel approach by utilizing the following processes in sequence: tDCS, a motor imagery (MI)-based brain-computer interface (BCI) with virtual reality (VR), and a motorized pedal end-effector. These are applied to enhance the brain plasticity and accelerate the motor recovery of post-stroke patients. The results are particularly relevant for post-stroke patients with severe lower-limb impairments, as the system proposed here provides motor training in a real-time closed-loop design, promoting cortical excitability around the foot area (Cz) while the patient directly commands with his/her brain signals the motorized pedal. This strategy has the potential to significantly improve rehabilitation outcomes. The study design follows an alternating treatment design (ATD), which involves a double-blind approach to measure improvements in both physical function and brain activity in post-stroke patients. The results indicate positive trends in the motor function, coordination, and speed of the affected limb, as well as sensory improvements. The analysis of event-related desynchronization (ERD) from EEG signals reveals significant modulations in Mu, low beta, and high beta rhythms. Although this study does not provide conclusive evidence for the superiority of adjuvant mental practice training over conventional therapy alone, it highlights the need for larger-scale investigations.Stroke is a clinical condition that consists of a sudden loss of focal neurological function due to an infarction or hemorrhage in the central nervous system (CNS) [The social and economic costs directly related to neuromuscular disabilities, such as stroke, are significant. This includes health and rehabilitation services, specific projects aimed at the labor market, education and professional training, social benefits, the distribution of assistive devices, and urban mobility [Studies conducted by Mohammadi, A., 2016 [Another type of innovative tool used to help generate neuroplasticity is a brain-computer interface (BCI). BCI is a communication system that measures the CNS activity and converts it into artificial commands to control end-applications [MI is defined as a dynamic event during which an individual mentally reproduces an action, and it encompasses two fundamental types: kinesthetic motor imagery (KMI) and visual motor imagery (VMI). KMI involves simulating movement sensations without actual execution, and VMI is primarily centered around visualizing movement execution. Both KMI and VMI engage overlapping neural networks found in regions like the primary motor cortex, supplementary motor areas, somatosensory cortex, and cerebellum [Notably, previous studies utilizing tDCS in association with MI-BCI have primarily focused on lower-limb rehabilitation using costly equipment or have centered on studies with healthy individuals. For instance, the investigation by Chew [The proposed method integrates cutting-edge technologies including tDCS, MI-BCI, VR, and a customized MP to facilitate the lower-limb rehabilitation of post-stroke patients. This innovative system also introduces a novel approach to BCI calibration, combining EEG signals from both MI and actual movements [