Brain and Mind Centre, Faculty of Medicine and Health, Translational Research Collective University of Sydney and Department of Neurology, Royal Prince Alfred Hospital, Sydney, Australia; Westmead Hospital, University of Sydney, Sydney, Australia; MRC Centre for Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK.
Central Clinical School, Faculty of Medicine and Health, University of Sydney, Australia.
Clin Neurophysiol. 2022 Apr;136:138-149. doi: 10.1016/j.clinph.2021.12.006. Epub 2021 Dec 29.
The excitability of motor and sensory axons of the main upper limb nerves were compared to characterise the differences between nerves and provide a guide for future studies in human diseases with median neuropathy at the wrist.
Axonal excitability studies were undertaken on median and ulnar motor (APB and ADM) and sensory axons (D2 and D5) and the superficial radial axons (D1) using a threshold tracking technique.
Compared to the median, ulnar motor axons had reduced early depolarising threshold electrotonus (TEd40(10-20 ms) p = 0.02) and superexcitability (p = 0.03). The ulnar sensory axons required a stronger stimulus (p = 0.02) and had a larger rheobase (p = 0.02) than median axons, but were otherwise comparable. The superficial radial axons were "fanned-in" compared to median, and to a lesser degree ulnar axons, with greater resting I/V slope. Mathematical modelling of the radial and median sensory axons suggested that a 15.1% reduction in conductances between nodal and internodal compartments accounted for 82% of this discrepancy.
The excitability parameters of motor and sensory axons are most comparable between median and ulnar nerves.
The present study demonstrates the feasibility of, and provides normative data for, axonal excitability recordings of the radial and ulnar nerves. We suggest the use of ulnar recordings as an alternative to the median nerve in the setting of compressive neuropathy at the wrist.
比较主要上肢神经的运动和感觉轴突的兴奋性，以表征神经之间的差异，并为腕部正中神经病变的人类疾病的未来研究提供指导。
采用阈跟踪技术对正中神经和尺神经的运动（APB 和 ADM）和感觉（D2 和 D5）轴突以及桡浅神经（D1）的轴突兴奋性进行研究。
与正中神经相比，尺神经运动轴突的早期去极化阈电紧张（TEd40(10-20ms)，p=0.02）和超兴奋性（p=0.03）降低。尺神经感觉轴突需要更强的刺激（p=0.02）和更大的基强度（p=0.02），但其他方面无明显差异。与正中神经相比，桡浅神经的“扇形”更为明显，与尺神经相比，静息 I/V 斜率更大。对桡神经和正中神经感觉轴突的数学建模表明，节点间和节间隔室之间的电导减少 15.1%，可解释 82%的这种差异。
运动和感觉轴突的兴奋性参数在正中神经和尺神经之间最具可比性。
本研究证明了桡神经和尺神经的轴突兴奋性记录是可行的，并提供了正常数据。我们建议在手腕压迫性神经病的情况下，使用尺神经记录代替正中神经。
