Muralidharan Abirami, Chae John, Taylor Dawn M
Department of Biomedical Engineering, Case Western Reserve University Cleveland, OH, USA.
Front Neurosci. 2011 Mar 25;5:39. doi: 10.3389/fnins.2011.00039. eCollection 2011.
This study examines the feasibility of using electroencephalograms (EEGs) to rapidly detect the intent to open one's hand in individuals with complete hand paralysis following a subcortical ischemic stroke. If detectable, this motor-planning activity could be used in real time to trigger a motorized hand exoskeleton or an electrical stimulation device that opens/closes the hand. While EEG-triggered movement-assist devices could restore function, they may also promote recovery by reinforcing the use of remaining cortical circuits. EEGs were recorded while participants were cued to either relax or attempt to extend their fingers. Linear-discriminant analysis was used to detect onset of finger-extension from the EEGs in a leave-one-trial-out cross-validation process. In each testing trial, the classifier was applied in pseudo-real-time starting from an initial hand-relaxed phase, through movement planning, and into the initial attempted-finger-extension phase (finger-extension phase estimated from typical time-to-movement-onset measured in the unaffected hand). The classifiers detected attempted-finger-extension at a significantly higher rate during both motor-planning and early attempted execution compared to rest. To reduce inappropriate triggering of a movement-assist device during rest, the classification threshold could be adjusted to require more certainty about one's intent to move before triggering a device. Additionally, a device could be set to activate only after multiple time samples in a row were classified as finger-extension events. These options resulted in some sessions with no false triggers while the person was resting, but moderate-to-high true trigger rates during attempted-movements.
本研究探讨了使用脑电图（EEG）快速检测皮质下缺血性中风后手部完全瘫痪个体张开手意图的可行性。如果这种意图可被检测到，这种运动计划活动可实时用于触发电动手部外骨骼或开合手部的电刺激装置。虽然脑电图触发的运动辅助装置可以恢复功能，但它们也可能通过加强剩余皮质回路的使用来促进恢复。在参与者被提示放松或尝试伸展手指时记录脑电图。在留一试验交叉验证过程中，使用线性判别分析从脑电图中检测手指伸展的开始。在每个测试试验中，分类器从初始手部放松阶段开始，经过运动计划，进入初始尝试手指伸展阶段（根据未受影响手部测量的典型运动开始时间估计手指伸展阶段），以伪实时方式应用。与休息时相比，分类器在运动计划和早期尝试执行期间检测到尝试手指伸展的比率显著更高。为了减少休息期间运动辅助装置的不适当触发，可以调整分类阈值，要求在触发装置之前对移动意图有更高的确定性。此外，可以设置装置仅在连续多个时间样本被分类为手指伸展事件后才激活。这些选项导致在某些情况下，当人休息时没有误触发，但在尝试运动期间有中到高的真触发率。
