The project is the first implementation of a BDBCI for walking that incorporates bilateral interhemispheric leg sensorimotor brain areas and represents a critical step toward restoring full ambulatory function in individuals living with spinal cord injury and paraplegia. The team’s results are reported in a paper published recently in the journal Brain Stimulation.
该项目是首个将双侧半球间腿部感觉运动脑区纳入步行的BDBCI项目，是脊髓损伤和截瘫患者恢复完全行走功能的关键一步。该团队的研究结果发表在最近的《大脑刺激》杂志上。
“Millions of people worldwide suffer from paralysis from spinal cord injury, with loss of lower-extremity motor and sensory function leading to wheelchair dependence and increased risk of serious secondary conditions including heart disease, osteoporosis and pressure ulcers,” said co-author Dr. An Do, UC Irvine associate professor of neurology. “Recovering the ability to walk ranks among the highest rehabilitation priorities for paralyzed individuals.”
“全世界有数百万人因脊髓损伤而瘫痪，下肢运动和感觉功能丧失，导致对轮椅的依赖，并增加了患心脏病、骨质疏松症和压力性溃疡等严重继发性疾病的风险，”合著者、加州大学欧文分校神经病学副教授An Do博士说。“对瘫痪患者来说，恢复行走能力是最重要的康复任务之一。”
He said that while robotic gait exoskeletons have emerged as a promising technology for restoring walking ability, existing systems rely on manual control and provide no sensory feedback, a significant limitation as impairment of the sensation of taking steps is known to reduce gait speed and increase the risk of falls.
他说，虽然机器人步态外骨骼已经成为恢复行走能力的一种很有前途的技术，但现有的系统依赖于手动控制，不提供感官反馈，这是一个重大的局限性，因为众所周知，走路的感觉受损会降低步态速度，增加跌倒的风险。
The team’s BDBCI apparatus directly addresses both these challenges. By decoding motor intent from electrocorticography signals recorded from the leg motor cortex and delivering artificial leg sensation through targeted electrical stimulation of the somatosensory cortex, it creates a closed-loop, brain-driven experience of walking.
该团队的BDBCI设备直接解决了这两个挑战。通过解码从腿部运动皮层记录的皮质电信号的运动意图，并通过有针对性的体感皮层电刺激来传递人工腿感，它创造了一个闭环，大脑驱动的行走体验。
“This work demonstrates that it’s feasible to restore both the motor and sensory dimensions of walking using a single, compact, embedded brain-computer interface system,” Do said. “We believe this lays a critical foundation for the development of fully implantable systems that could one day give paraplegic patients a meaningful and natural sense of movement.”
“这项工作表明，使用一个单一的、紧凑的嵌入式脑机接口系统来恢复步行的运动和感觉维度是可行的，”Do说。“我们相信这为完全植入式系统的发展奠定了重要的基础，有朝一日，这种系统可能会给截瘫患者带来有意义的、自然的运动感。”
The participant in the study was a 50-year-old woman undergoing epilepsy evaluation with bilateral interhemispheric subdural electrocorticography implantation. She operated the BDBCI-controlled exoskeleton across 10 exercises, rapidly achieving a high level of performance, which demonstrated the system’s accessibility and reliability, according to the researchers.
该研究的参与者是一名50岁的女性，正在接受双侧半球间硬脑膜下皮质电成像植入评估癫痫。据研究人员称，她操作bdbci控制的外骨骼进行了10次练习，迅速达到了高水平的性能，这证明了该系统的可访问性和可靠性。
To validate artificial sensory feedback, the subject completed a blind step-counting task, correctly identifying steps with an overall accuracy of almost 93 percent. In an additional sensory discrimination task, she identified right leg, left leg and null (no stimulation) feelings with 96, 84 and 100 percent accuracy, respectively. The participant confirmed in all 10 runs that exoskeleton steps triggered matching contralateral leg sensations and reported that the sensory feedback aided task performance. No adverse events were noted throughout the study, the researchers said.
为了验证人工感官反馈，受试者完成了一项盲数步数任务，正确识别步数的总体准确率接近93%。在另一项感官辨别任务中，她分别以96%、84%和100%的准确率识别了右腿、左腿和没有刺激的感觉。参与者在所有10次跑步中证实，外骨骼步骤触发了匹配的对侧腿部感觉，并报告感觉反馈有助于任务表现。研究人员说，在整个研究过程中没有发现不良事件。
A key innovation of this project was the use of bilateral interhemispheric electrocorticography implants to access the leg motor and sensory cortices in the medial wall of the brain along the interhemispheric fissure.
这个项目的一个关键创新是使用双侧半球间皮质电成像植入物，沿着半球间裂进入大脑内侧壁的腿部运动和感觉皮层。
“Although interhemispheric ECoG implantation is more complex than other conventional approaches, our team demonstrated that it can be performed safely and yields superior results,” said co-author Dr. Charles Liu, professor of neurological surgery and director of the USC Neurorestoration Center at Keck School of Medicine of USC. “The leg motor cortex in the interhemispheric region provides more robust and reliable neural signal modulation associated with leg movements, making it likely the most optimal recording site for BCI walking applications.”
“虽然半球间ECoG植入比其他传统方法更复杂，但我们的团队证明它可以安全进行并产生更好的结果，”南加州大学凯克医学院神经外科教授兼南加州大学神经修复中心主任查尔斯刘博士说。“大脑半球间区的腿部运动皮层提供了与腿部运动相关的更强大、更可靠的神经信号调制，使其成为脑机接口行走应用的最佳记录部位。”
Artificial sensation was delivered through direct cortical electrical stimulation, a technique the researchers identify as the safest and most practical option for eliciting leg sensation in ambulatory settings. Because ECoG electrode arrays can be implanted to simultaneously cover both the motor cortex for movement decoding and the somatosensory cortex for sensory stimulation, the BDBCI system incurs no additional surgical risk. Long-term cortical electrical stimulation has also been demonstrated as safe in existing commercial devices approved by the U.S. Food and Drug Administration.
人工感觉是通过直接皮层电刺激传递的，研究人员认为这是在移动环境中引起腿部感觉的最安全、最实用的选择。由于ECoG电极阵列可以同时植入用于运动解码的运动皮层和用于感觉刺激的体感皮层，因此BDBCI系统不会带来额外的手术风险。美国食品和药物管理局批准的现有商用设备也证明了长期皮质电刺激是安全的。
The entire BDBCI system was implemented on a compact, portable, embedded platform consisting of three 48-megahertz microcontrollers that jointly perform all system functions – including neural signal acquisition, real-time decoding, electrical stimulation and wireless communications – without reliance on a tethered computing system.
整个BDBCI系统是在一个紧凑、便携的嵌入式平台上实现的，该平台由三个48兆赫的微控制器组成，这些微控制器共同执行所有系统功能，包括神经信号采集、实时解码、电刺激和无线通信，而不依赖于固定的计算系统。
“This type of portability is necessary to be practical for patients’ everyday use. We hope that our system can serve as a prototypical example for such technologies henceforth,” said lead author Jeffrey Lim, UC Irvine postdoctoral scholar in biomedical engineering.
“这种便携性对于病人的日常使用是必要的。我们希望我们的系统可以成为今后此类技术的原型，”加州大学欧文分校生物医学工程博士后学者Jeffrey Lim说。
The robotic gait exoskeleton used in the study was the Ekso GT from Ekso Bionics, an FDA-approved powered device. The embedded design positions the BDBCI as a benchtop version of an implantable system; it’s the first of its kind to combine bilateral lower-extremity artificial sensation with motor decoding in a single BDBCI robotic gait exoskeleton.
研究中使用的机器人步态外骨骼是Ekso仿生公司的Ekso GT，这是一款获得fda批准的动力设备。嵌入式设计将BDBCI定位为可植入系统的台式版本；这是同类产品中首次将双侧下肢人工感觉与运动解码结合在一个BDBCI机器人步态外骨骼中。
“We are looking ahead to a fully implantable version of the BDBCI in which a skull-mounted unit connects via a subcutaneous cable to a chest wall-implanted unit housing all signal processing, stimulation and wireless communication electronics,” said co-author Payam Heydari, UC Irvine professor of electrical engineering and computer science. “Such a system would eliminate transdermal components that pose infection risks and enable chronic implantation in paraplegic spinal cord injury patients.”
加州大学欧文分校电子工程和计算机科学教授帕亚姆·海达里(Payam Heydari)说：“我们期待着一个完全可植入的BDBCI版本，其中一个安装在头骨上的单元通过皮下电缆连接到胸壁植入的单元，该单元包含所有信号处理、刺激和无线通信电子设备。这样的系统将消除造成感染风险的透皮成分，并使截瘫脊髓损伤患者能够长期植入。”
He added that further miniaturization is possible through advanced multilayer printed circuit boards, smaller surface-mounted components and conventional semiconductor system-on-a-chip integration. Earlier work at UC Irvine achieved significant size reduction and energy efficiency through integrated circuit implementation.
他补充说，通过先进的多层印刷电路板、更小的表面安装组件和传统的半导体片上系统集成，进一步小型化是可能的。加州大学欧文分校的早期工作通过集成电路实现了显著的尺寸减小和能源效率。
According to co-author Zoran Nenadic, UC Irvine professor of biomedical engineering, further technical advances can be achieved via refinement of motor decoding algorithms and mitigation of electrical stimulation artifacts, enabling future systems to operate more robustly while providing continuous artificial sensation. “Our ultimate goal is to test the function of such a system on people with complete leg paralysis, demonstrating its potential to mimic the function of an intact sensorimotor loop,” he said.
据合著者、加州大学欧文分校生物医学工程教授佐兰·内纳迪奇(Zoran Nenadic)称，进一步的技术进步可以通过改进电机解码算法和减轻电刺激伪影来实现，使未来的系统在提供连续人工感觉的同时运行更稳健。他说：“我们的最终目标是在腿部完全瘫痪的人身上测试这种系统的功能，证明它有潜力模仿完整的感觉运动回路的功能。”
Co-author Richard Andersen, Caltech’s James G. Boswell Professor of Neuroscience, said that his and other laboratories have been working for several years on bidirectional interfaces to restore somatosensations to the hands of tetraplegic subjects so they can manipulate objects with robotic hands.
合著者理查德·安德森(Richard Andersen)是加州理工学院的詹姆斯·G·博斯韦尔(James G. Boswell)神经科学教授，他说他和其他实验室几年来一直在研究双向界面，以恢复四肢瘫痪患者的手部体感，这样他们就可以用机器人手操纵物体。
“This study by UC Irvine’s Jeffrey Lim and colleagues represents an important proof of concept for a bidirectional interface for walking, providing somatosensory feedback to the legs while a paralyzed participant brain-controlled a robotic gait exoskeleton,” Andersen said. “Paraplegic subjects using exoskeletons currently lack natural somatosensory feedback and must rely on visual feedback. This research provides a new avenue for more naturalistic and effective use of walking exoskeletons.”
安德森说：“加州大学欧文分校的杰弗里·林（Jeffrey Lim）及其同事的这项研究代表了双向行走接口概念的重要证明，当瘫痪参与者的大脑控制机器人步态外骨骼时，它为腿部提供体感反馈。”“使用外骨骼的截瘫患者目前缺乏自然的体感反馈，必须依靠视觉反馈。这项研究为更自然、更有效地使用行走外骨骼提供了一条新途径。”
