感觉、运动或自主神经系统的异常病理活动与疼痛和痉挛等多种神经机能障碍有关。千频交流电(kilohertz frequency alternating current,KHFAC)刺激是一种阻断异常病理活动在外周神经内传导的有效方法,它在缓解相关神经机能障碍方面具有...感觉、运动或自主神经系统的异常病理活动与疼痛和痉挛等多种神经机能障碍有关。千频交流电(kilohertz frequency alternating current,KHFAC)刺激是一种阻断异常病理活动在外周神经内传导的有效方法,它在缓解相关神经机能障碍方面具有临床应用潜力。KHFAC产生的神经传导阻断受千频信号波形和参数、阻断电极设置和位置以及神经纤维类型和直径等因素影响,具有快速性、可控性、可逆性、局部作用和副作用小的特点。但是,在产生完全传导阻断前,KHFAC首先在靶向神经上激活一簇高频初始放电,这种初始响应可能导致肌肉抽搐或疼痛感。同时,在撤去KHFAC后处于阻断状态的靶向神经需要经历一段时间才能恢复正常传导能力,这是该技术导致的后续效应。目前,关于KHFAC阻断神经传导的生物物理机制假说包括千频信号诱发K+通道激活和Na+通道失活。本文首先介绍了KHFAC技术的电生理实验研究方法和计算模型仿真方法,然后综述目前关于KHFAC作用下神经传导阻断的研究进展,重点论述初始响应特性及消除方法、传导阻断的后续效应、刺激波形和参数的影响、电极设置与位置的影响以及该技术潜在的临床应用,同时归纳KHFAC阻断神经传导的生物物理机制,最后对该技术未来的相关研究进行展望。展开更多
Objective: To quantify temperature induced changes (=Uhthoff phenomenon) in ce ntral motor conduction and their relation to clinical motor deficits in 20 multi ple sclerosis (MS) patients. Methods: Self assessment of ...Objective: To quantify temperature induced changes (=Uhthoff phenomenon) in ce ntral motor conduction and their relation to clinical motor deficits in 20 multi ple sclerosis (MS) patients. Methods: Self assessment of vulnerability to tempe rature and clinical examination were performed. We used motor evoked potentials to measure central motor conduction time (CMCT) and applied the triple stimulat ion technique (TST) to assess conduction failure. The TST allows an accurate qua ntification of the proportion of conducting central motor neurons, expressed by the TST amplitude ratio (TST AR). Results: Temperature induced changes of TST AR were significantly more marked in patients with prolonged CMCT (P=0.037). The re was a significant linear correlation between changes of TST AR and walking v elocity (P=0.0002). Relationships were found between pronounced subjective vulne rability to temperature and (i) abnormal CMCT (P=0.02), (ii) temperature induced changes in TST AR (P=0.04) and (iii) temperature induced changes in walking ve locity (P=0.04). CMCT remained virtually unchanged by temperature modification. Conclusions: Uhthoff phenomena in the motor system are due to varying degrees of conduction block and associated with prolonged CMCT. In contrast to conduction block, CMCT is not importantly affected by temperature. Significance: This is th e first study quantifying the Uhthoff phenomenon in the pyramidal tract of MS pa tients. The results suggest that patients with central conduction slowing are pa rticularly vulnerable to develop temperature dependent central motor conduction blocks.展开更多
文摘感觉、运动或自主神经系统的异常病理活动与疼痛和痉挛等多种神经机能障碍有关。千频交流电(kilohertz frequency alternating current,KHFAC)刺激是一种阻断异常病理活动在外周神经内传导的有效方法,它在缓解相关神经机能障碍方面具有临床应用潜力。KHFAC产生的神经传导阻断受千频信号波形和参数、阻断电极设置和位置以及神经纤维类型和直径等因素影响,具有快速性、可控性、可逆性、局部作用和副作用小的特点。但是,在产生完全传导阻断前,KHFAC首先在靶向神经上激活一簇高频初始放电,这种初始响应可能导致肌肉抽搐或疼痛感。同时,在撤去KHFAC后处于阻断状态的靶向神经需要经历一段时间才能恢复正常传导能力,这是该技术导致的后续效应。目前,关于KHFAC阻断神经传导的生物物理机制假说包括千频信号诱发K+通道激活和Na+通道失活。本文首先介绍了KHFAC技术的电生理实验研究方法和计算模型仿真方法,然后综述目前关于KHFAC作用下神经传导阻断的研究进展,重点论述初始响应特性及消除方法、传导阻断的后续效应、刺激波形和参数的影响、电极设置与位置的影响以及该技术潜在的临床应用,同时归纳KHFAC阻断神经传导的生物物理机制,最后对该技术未来的相关研究进行展望。
文摘Objective: To quantify temperature induced changes (=Uhthoff phenomenon) in ce ntral motor conduction and their relation to clinical motor deficits in 20 multi ple sclerosis (MS) patients. Methods: Self assessment of vulnerability to tempe rature and clinical examination were performed. We used motor evoked potentials to measure central motor conduction time (CMCT) and applied the triple stimulat ion technique (TST) to assess conduction failure. The TST allows an accurate qua ntification of the proportion of conducting central motor neurons, expressed by the TST amplitude ratio (TST AR). Results: Temperature induced changes of TST AR were significantly more marked in patients with prolonged CMCT (P=0.037). The re was a significant linear correlation between changes of TST AR and walking v elocity (P=0.0002). Relationships were found between pronounced subjective vulne rability to temperature and (i) abnormal CMCT (P=0.02), (ii) temperature induced changes in TST AR (P=0.04) and (iii) temperature induced changes in walking ve locity (P=0.04). CMCT remained virtually unchanged by temperature modification. Conclusions: Uhthoff phenomena in the motor system are due to varying degrees of conduction block and associated with prolonged CMCT. In contrast to conduction block, CMCT is not importantly affected by temperature. Significance: This is th e first study quantifying the Uhthoff phenomenon in the pyramidal tract of MS pa tients. The results suggest that patients with central conduction slowing are pa rticularly vulnerable to develop temperature dependent central motor conduction blocks.
