| Author: | Lin, Legeng |
| Title: | Sensorimotor integrated exo-neuro-musculo-skeleton (ENMS) with electro-vibro-feedback for wrist/hand rehabilitation after stroke |
| Advisors: | Hu, Xiaoling (BME) |
| Degree: | Ph.D. |
| Year: | 2025 |
| Department: | Department of Biomedical Engineering |
| Pages: | xx, 134 pages : color illustrations |
| Language: | English |
| Abstract: | Sensorimotor integration (SMI) is often disrupted after stroke, hindering the functional recovery effects of robot-assisted upper limb (UL) training. Although proprioception experiences could be provided in movement assisted by robots with pure mechanical actuation (pure robot), the rehabilitative effects on UL are still limited, especially for the distal joints, i.e., wrist/hand (W/H). Neuromuscular electrical stimulation (NMES) and mechanical robot hybrid system (NMES-robot) could lead to faster motor recovery for W/H joints than the pure robot. However, NMES as electrical stimulations is not applicable to flexor digitorum (FD) because it leads to pain, muscle fatigue, and higher muscle spasticity on FD in long-term usage. Compared to NMES, focal vibratory stimulation (FVS) without causing muscle contraction holds the potential to be more suitable than NMES for somatosensory priming on FD, which usually has sufficient residual voluntary force after stroke. However, little is known about the differences between the transient neuromodulatory effects of FVS and NMES poststroke. Besides, little work has been done on the optimized integration of FVS and NMES in robot design for somatosensory priming of target muscles in rehabilitation after stroke. Furthermore, the feasibility and rehabilitative effects of the integrated device with somatosensory priming from NMES and FVS are still unclear in robot-assisted rehabilitation training. Therefore, the main objectives of this study were: (i) to investigate and compare the immediate neuromodulatory effects of FVS and NMES at the cortical level in poststroke and unimpaired persons; (ii) to integrate FVS and NMES into a hybrid robotic system for W/H rehabilitation after stroke; (iii) to evaluate the effectiveness of the new system in W/H rehabilitation and analyze the neuroplastic mechanisms of functional recovery. The study was conducted as follows: The first section investigated the immediate neuromodulatory effects of FVS and NMES at the cortical level after stroke. Cortical responses in persons with chronic stroke (N = 15) and unimpaired controls (N = 15) were measured by whole-brain electroencephalography (EEG) when FVS and NMES at different intensities were applied transcutaneously to the forearm muscles, i.e. extensor digitorum (ED) and FD. Results showed that both FVS and NMES effectively activated the sensorimotor cortex after stroke. However, FVS was particularly effective in eliciting transient involuntary attention, while NMES primarily fostered the cortical responses of the targeted muscles in the contralesional motor cortex. The second section designed a novel electromyography (EMG)-driven exoneuromusculoskeleton with electro-vibro-feedback (ENMS-EVF) that integrates NMES on the ED and FVS on the FD into a wearable exoskeleton with soft pneumatic muscles for somatosensory priming in poststroke W/H rehabilitation. Participants with chronic stroke (N = 7) were recruited to participate in a validation test and a preliminary training program containing 20-session rehabilitation training assisted by the new system. The evaluation outcomes were measured before and after the training program, as well as after the 10th session of training, including sensorimotor clinical scores. The results validated the effectiveness of the system's design and parameter and task settings for the intended rehabilitative applications. The ENMS-EVF-assisted training program could facilitate sensorimotor improvement in the affected upper limb of the participants with chronic stroke. The third section evaluated the long-term effectiveness of the ENMS-EVF system in W/H rehabilitation and analyzed the neuroplastic mechanisms of functional sensorimotor recovery after rehabilitation training. Participants with chronic stroke (N = 15) were recruited to undergo a 20-session rehabilitation training program assisted by ENMS-EVF. The evaluation outcomes were measured before, after, and three months after the training, including sensorimotor clinical scores and corticomuscular electrophysiological features. The results demonstrated that the system was feasible and effective for improving UL sensorimotor functions in robot-assisted somatosensory priming after stroke because of sustained neuroplasticity of enhanced contralateral control of agonist muscles and ascending somatosensory feedback from antagonist muscles during W/H extension. In conclusion, this study compared the immediate neuromodulatory effects of FVS and NMES, confirming the effectiveness of FVS for somatosensory stimulation and contributing to our understanding of their potential tailored applications in stroke rehabilitation. In addition, this study designed and validated the novel ENMS-EVF system, which is feasible and effective for assisting stroke patients in improving sensorimotor functions of UL after the training program. Moreover, long-term rehabilitation effects and neuroplasticity changes after ENMS-EVF-assisted training sheds light on the rehabilitative effects of robot-assisted somatosensory priming on sensorimotor functions and its underlying cortical and pathway-specific corticomuscular mechanisms after stroke, providing significant insights for developing more effective interventions toward SMI rehabilitation in the future. |
| Rights: | All rights reserved |
| Access: | open access |
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