Eugen Lontis R, Yoshida Ken, Jensen Winnie
Annu Int Conf IEEE Eng Med Biol Soc. 2018 Jul;2018:3533-3536. doi: 10.1109/EMBC.2018.8512934.
Phantom limb pain (PLP) is a frequent consequence of amputation. Recent evidence suggests that the pathophysiological mechanisms of PLP are related to neuroplastic changes in the cortex, as consequence of the lost sensory feedback. Formation of referred sensation areas (RSAs) may follow amputation. Sensations may be evoked in the lost body part upon stimulation of RSAs that may be exploited as artificial sensory feedback. The RSAs, however, have also shown to change over time. Features of RSAs in the case of a 36 year old male with right arm amputation aiming to identify placement of electrodes for sensory feedback are reported in this paper. The arm was amputated at shoulder level following patient's request five years after a vehicle accident that resulted in brachial plexus injury and consequent severe arm paralysis with residual sensory functionality up to 20 %. RSAs were characterized over five sessions within 27 days using mechanical stimuli (brushing over the area or applying light pressure). Tests of electrical stimuli were applied hrough two surface electrodes covering one or multiple RSAs to generate evoked sensations. Location and extent of RSAs as well as the type and location of sensations evoked in the phantom limb were stable within the session (tested up to 30 minutes) and dynamic between sessions. Partial overlapping of RSAs with associated evoked sensation of same or different type was observed for different sessions. Various painful and non-painful sensations were evoked by both mechanical and electrical stimuli dependent on location of the applied stimulus and assessment time. Mechanical andelectrical stimuli applied at the same location evoked the same or different types of sensation in the phantom limb. RSAs may be a promising pathway for delivering sensory feedback for PLP treatment. Features, however, of RSAs may highly influence the efficiency of the PLP treatment.
幻肢痛（PLP）是截肢常见的后果。最近的证据表明，PLP的病理生理机制与皮质的神经可塑性变化有关，这是感觉反馈丧失的结果。截肢后可能会形成牵涉感觉区（RSA）。刺激RSA时，可能会在已缺失的身体部位诱发感觉，这些感觉可被用作人工感觉反馈。然而，RSA也显示会随时间变化。本文报告了一名36岁右臂截肢男性患者的RSA特征，旨在确定用于感觉反馈的电极放置位置。该患者在一次车祸导致臂丛神经损伤及严重手臂麻痹（残余感觉功能达20%）五年后，应其要求在肩部水平进行了截肢。在27天内分五个阶段使用机械刺激（在该区域轻刷或施加轻压）对RSA进行了特征描述。通过覆盖一个或多个RSA的两个表面电极施加电刺激测试以产生诱发感觉。RSA的位置和范围以及幻肢中诱发感觉的类型和位置在一个阶段内是稳定的（测试长达30分钟），而在不同阶段之间是动态变化的。不同阶段观察到RSA与相同或不同类型的相关诱发感觉部分重叠。机械和电刺激根据所施加刺激的位置和评估时间会诱发各种疼痛和非疼痛感觉。在同一位置施加的机械和电刺激在幻肢中诱发相同或不同类型的感觉。RSA可能是为PLP治疗提供感觉反馈的一条有前景的途径。然而，RSA的特征可能会极大地影响PLP治疗的效果。
