基于电刺激的上肢截肢者诱发手指幻肢感初步研究
The Preliminary Research of Evoked Phantom Finger Sensations Based on Electrical Stimulation for Upper Limb Amputee
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摘要: 目前商用假肢缺乏有效的感觉反馈机制, 人们通过机械刺激可进行间接的感觉反馈, 但仍不能产生“自然”感觉。一些研究者们通过神经内植入式电刺激可以帮助使用者获取“自然”感觉, 这种有创的方式需要进行手术且对电极材料的要求很严格。相比之下, 经皮电刺激更易实现, 然而目前的研究还缺乏有效的控制策略来主动调控电刺激参数。因此, 该文对经皮电刺激诱发手指幻肢感进行了初步研究, 并结合脑电信号(EEG)特征, 探究了一种客观的方法来评价电刺激参数与所诱发的手指幻肢感觉的关系, 使得实现电刺激参数的主动调控成为可能。结果初步表明了通过经皮电刺激可以诱发上臂截肢患者幻肢手指收缩的感觉;并且, 通过分析脑电地形分布可建立刺激的位置与所诱发感觉的位置之间的关系;通过提取事件相关电位并分析其曲线特征, 可判断所施加的电刺激强度是否足够诱发明显的幻肢感觉。该研究有助于在电刺激诱发幻肢感的研究中实现刺激参数的自动调控。Abstract: The current commercial prostheses are lack of effective sensory feedback mechanism. Indirect stimulation methods such as mechanical stimulation were applied to achieve sensory feedback in some work, but they cannot evoke “natural” sensations. Some researchers evoked somatic sensations by intra-neural stimulation, which is invasive and with high restriction on electrode materials. In comparison, transcutaneous electrical stimulation (TNES) is easier to be implemented. Unfortunately, there is still no effective strategy to autonomous control electrical stimulation parameters. In this paper, we conducted a preliminary research on the relationship between electrical stimulation parameters and evoked somatic sensation based on Electroencephalogram (EEG) analysis. The experimental results proved that the phantom sensation of fingers can be evoked by TNES. In addition, the relationship between the position of stimulation and the position of evoked sensation be analyzed according to the EEG distribution. And it can be determined whether the stimulation intensity is enough to evoke obvious phantom sensation, by analyzing its curve characteristics of event-related potential (ERP). This work can be helpful to automatically control electrical stimulation parameters for evoking phantom sensations in the future.