Heidelberg University Hospital, Spinal Cord Injury Center, Schlierbacher Landstrasse 200a, 69118 Heidelberg, Germany.
Artif Intell Med. 2013 Oct;59(2):133-42. doi: 10.1016/j.artmed.2013.07.004. Epub 2013 Sep 13.
The bilateral loss of the grasp function associated with a lesion of the cervical spinal cord severely limits the affected individuals' ability to live independently and return to gainful employment after sustaining a spinal cord injury (SCI). Any improvement in lost or limited grasp function is highly desirable. With current neuroprostheses, relevant improvements can be achieved in end users with preserved shoulder and elbow, but missing hand function.
The aim of this single case study is to show that (1) with the support of hybrid neuroprostheses combining functional electrical stimulation (FES) with orthoses, restoration of hand, finger and elbow function is possible in users with high-level SCI and (2) shared control principles can be effectively used to allow for a brain-computer interface (BCI) control, even if only moderate BCI performance is achieved after extensive training.
The individual in this study is a right-handed 41-year-old man who sustained a traumatic SCI in 2009 and has a complete motor and sensory lesion at the level of C4. He is unable to generate functionally relevant movements of the elbow, hand and fingers on either side. He underwent extensive FES training (30-45min, 2-3 times per week for 6 months) and motor imagery (MI) BCI training (415 runs in 43 sessions over 12 months). To meet individual needs, the system was designed in a modular fashion including an intelligent control approach encompassing two input modalities, namely an MI-BCI and shoulder movements.
After one year of training, the end user's MI-BCI performance ranged from 50% to 93% (average: 70.5%). The performance of the hybrid system was evaluated with different functional assessments. The user was able to transfer objects of the grasp-and-release-test and he succeeded in eating a pretzel stick, signing a document and eating an ice cream cone, which he was unable to do without the system.
This proof-of-concept study has demonstrated that with the support of hybrid FES systems consisting of FES and a semiactive orthosis, restoring hand, finger and elbow function is possible in a tetraplegic end-user. Remarkably, even after one year of training and 415 MI-BCI runs, the end user's average BCI performance remained at about 70%. This supports the view that in high-level tetraplegic subjects, an initially moderate BCI performance cannot be improved by extensive training. However, this aspect has to be validated in future studies with a larger population.
与颈脊髓损伤相关的双侧抓握功能丧失严重限制了受影响个体的独立生活能力和重返工作岗位的能力。任何对丧失或有限的抓握功能的改善都是非常可取的。目前，使用神经假体可以改善那些肩部和肘部功能保留但手部功能缺失的终端用户的相关功能。
本单病例研究的目的是证明：（1）在结合功能性电刺激（FES）和矫形器的混合神经假体的支持下，高位脊髓损伤患者的手部、手指和肘部功能可以得到恢复；（2）共享控制原则可以有效地用于允许脑机接口（BCI）控制，即使在经过广泛的训练后，仅能实现中等程度的 BCI 性能。
本研究中的个体是一名 41 岁的右利手男性，他于 2009 年因外伤性脊髓损伤，C4 水平完全性运动和感觉损伤。他无法在两侧产生具有功能相关性的肘部、手部和手指运动。他接受了广泛的 FES 训练（30-45min，每周 2-3 次，持续 6 个月）和运动想象（MI）BCI 训练（12 个月内 43 次共 415 次运行）。为了满足个人需求，系统采用模块化设计，包括一种智能控制方法，包含两种输入模式，即 MI-BCI 和肩部运动。
经过一年的训练，终端用户的 MI-BCI 性能范围为 50%至 93%（平均：70.5%）。通过不同的功能评估对混合系统的性能进行了评估。用户能够进行抓握释放测试的物体转移，并且他成功地吃了椒盐脆饼棒、签署了文件和吃了冰淇淋蛋筒，而没有该系统他是无法做到的。
这项概念验证研究表明，在混合 FES 系统（由 FES 和半主动矫形器组成）的支持下，手部、手指和肘部功能的恢复是可能的，在四肢瘫痪的终端用户中。值得注意的是，即使经过一年的训练和 415 次 MI-BCI 运行，终端用户的平均 BCI 性能仍保持在 70%左右。这支持了这样一种观点，即在高位四肢瘫痪患者中，初始的中等 BCI 性能不能通过广泛的训练得到改善。然而，这方面需要在未来的更大人群研究中得到验证。
