肌萎缩侧索硬化症的病理生理学：从手部分离现象中得到的启示。
ALS pathophysiology: insights from the split-hand phenomenon.
机构信息
Sydney Medical School Westmead, University of Sydney, Sydney, Australia.
Neuroscience Research Australia, Sydney, Australia; Prince of Wales Clinical School, University of New South Wales, Sydney, Australia.
出版信息
Clin Neurophysiol. 2014 Jan;125(1):186-93. doi: 10.1016/j.clinph.2013.07.022. Epub 2013 Sep 16.
OBJECTIVE
The aim of the present study was to assess whether peripheral mechanisms, mediated through axonal dysfunction, may contribute to development of the split-hand in amyotrophic lateral sclerosis (ALS).
METHODS
Median and ulnar nerve motor axonal excitability studies were undertaken on 21 ALS patients with motor responses recorded over the abductor pollicis brevis (APB), abductor digit minimi (ADM) and first dorsal interosseous (FDI) muscles, and results compared to 24 controls.
RESULTS
The split-hand index (SI), an objective biomarker of preferential atrophy of APB and FDI muscles, was significantly reduced in ALS (SI(ALS) 7.8 ± 1.7, SICONTROLS 13.1 ± 1.1, P<0.0001). Axonal excitability studies identified significant prolongation of strength-duration time constant in ALS patients when recording over the APB (P<0.05) and ADM axons (P<0.05) but not FDI axons (P=0.22). Greater changes in depolarising threshold electrotonus were also evident across the range of intrinsic hand muscles and were accompanied by increases of superexcitability in APB (P<0.01) and FDI (P<0.05) axons.
CONCLUSION
The present study reinforces the significance of the split-hand phenomenon in ALS and argues against a significant peripheral contribution in the underlying development.
SIGNIFICANCE
Axonal dysfunction may appear as a downstream process that develops secondary to the intrinsic pathophysiological origins of ALS.
目的
本研究旨在评估通过轴突功能障碍介导的周围机制是否可能导致肌萎缩侧索硬化症（ALS）中出现手部分离现象。
方法
对 21 例 ALS 患者进行正中神经和尺神经运动轴突兴奋性研究，在拇短展肌（APB）、小指展肌（ADM）和第一骨间背侧肌（FDI）上记录运动反应，并与 24 例对照进行比较。
结果
手部分离指数（SI），即 APB 和 FDI 肌肉优先萎缩的客观生物标志物，在 ALS 中显著降低（SI(ALS) 7.8 ± 1.7，SICONTROLS 13.1 ± 1.1，P<0.0001）。当记录 APB（P<0.05）和 ADM 轴突（P<0.05）时，轴突兴奋性研究发现 ALS 患者的强度-持续时间时间常数明显延长，但 FDI 轴突（P=0.22）则没有。在整个内在手部肌肉中，去极化阈电紧张的变化也更为明显，并且伴随着 APB（P<0.01）和 FDI（P<0.05）轴突的超兴奋性增加。
结论
本研究加强了手部分离现象在 ALS 中的重要性，并认为在潜在发展中，外周贡献并不显著。
意义
轴突功能障碍可能表现为继发于 ALS 内在病理生理起源的下游过程。
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