Nguyen Hoai Son, Luu Trieu Phat
Group of Advanced Computations in Engineering Science, HCMC University of Technology and Education, Ho Chi Minh City, Vietnam.
Noninvasive Brain-Machine Interface System Laboratory, Department of Electrical and Computer Engineering, University of Houston, Houston, TX, United States.
Front Hum Neurosci. 2021 Apr 30;15:622535. doi: 10.3389/fnhum.2021.622535. eCollection 2021.
Pathological tremor is the most common motor disorder in adults and characterized by involuntary, rhythmic muscular contraction leading to shaking movements in one or more parts of the body. Functional Electrical Stimulation (FES) and biomechanical loading using wearable orthoses have emerged as effective and non-invasive methods for tremor suppression. A variety of upper-limb orthoses for tremor suppression have been introduced; however, a systematic review of the mechanical design, algorithms for tremor extraction, and the experimental design is still missing. To address this gap, we applied a standard systematic review methodology to conduct a literature search in the PubMed and PMC databases. Inclusion criteria and full-text access eligibility were used to filter the studies from the search results. Subsequently, we extracted relevant information, such as suppression mechanism, system weights, degrees of freedom (DOF), algorithms for tremor estimation, experimental settings, and the efficacy. The results show that the majority of tremor-suppression orthoses are active with 47% prevalence. Active orthoses are also the heaviest with an average weight of 561 ± 467 g, followed by semi-active 486 ± 395 g, and passive orthoses 191 ± 137 g. Most of the orthoses only support one DOF (54.5%). Two-DOF and three-DOF orthoses account for 33 and 18%, respectively. The average efficacy of tremor suppression using wearable orthoses is 83 ± 13%. Active orthoses are the most efficient with an average efficacy of 83 ± 8%, following by the semi-active 77 ± 19%, and passive orthoses 75 ± 12%. Among different experimental setups, bench testing shows the highest efficacy at 95 ± 5%, this value dropped to 86 ± 8% when evaluating with tremor-affected subjects. The majority of the orthoses (92%) measured voluntary and/or tremorous motions using biomechanical sensors (e.g., IMU, force sensor). Only one system was found to utilize EMG for tremor extraction. Our review showed an improvement in efficacy of using robotic orthoses in tremor suppression. However, significant challenges for the translations of these systems into clinical or home use remain unsolved. Future challenges include improving the wearability of the orthoses (e.g., lightweight, aesthetic, and soft structure), and user control interfaces (i.e., neural machine interface). We also suggest addressing non-technical challenges (e.g., regulatory compliance, insurance reimbursement) to make the technology more accessible.
病理性震颤是成年人中最常见的运动障碍，其特征是不自主的、有节奏的肌肉收缩，导致身体一个或多个部位出现抖动。功能性电刺激（FES）和使用可穿戴矫形器的生物力学负荷已成为抑制震颤的有效且非侵入性的方法。已经推出了多种用于抑制震颤的上肢矫形器；然而，对于其机械设计、震颤提取算法和实验设计仍缺乏系统的综述。为了填补这一空白，我们应用标准的系统综述方法在PubMed和PMC数据库中进行文献检索。使用纳入标准和全文获取资格从检索结果中筛选研究。随后，我们提取了相关信息，如抑制机制、系统重量、自由度（DOF）、震颤估计算法、实验设置和疗效。结果表明，大多数震颤抑制矫形器是主动式的，患病率为47%。主动式矫形器也是最重的，平均重量为561±467克，其次是半主动式486±395克，被动式矫形器191±137克。大多数矫形器仅支持一个自由度（54.5%）。两自由度和三自由度矫形器分别占33%和18%。使用可穿戴矫形器抑制震颤的平均疗效为83±13%。主动式矫形器效率最高，平均疗效为83±8%，其次是半主动式77±19%，被动式矫形器75±12%。在不同的实验设置中，台架测试显示出最高的疗效，为95±5%，当对震颤患者进行评估时，该值降至86±8%。大多数矫形器（92%）使用生物力学传感器（如惯性测量单元、力传感器）测量自愿和/或震颤运动。仅发现一个系统利用肌电图进行震颤提取。我们的综述表明，使用机器人矫形器抑制震颤的疗效有所提高。然而，将这些系统转化为临床或家庭使用仍面临重大挑战。未来的挑战包括提高矫形器的可穿戴性（如轻便、美观和柔软结构）以及用户控制界面（即神经机器接口）。我们还建议应对非技术挑战（如法规合规、保险报销），以使该技术更易于获得。
