Department of Neurology, University of Ulm, 89081 Ulm, Germany
German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany.
J Neurol Neurosurg Psychiatry. 2020 Sep;91(9):991-998. doi: 10.1136/jnnp-2020-323331. Epub 2020 Jul 14.
A recent neuroanatomical staging scheme of amyotrophic lateral sclerosis (ALS) indicates that a cortical lesion may spread, as a network disorder, both at the cortical level and via corticofugal tracts, including corticospinal projections providing direct monosynaptic input to α-motoneurons. These projections are involved preferentially and early in ALS. If these findings are clinically relevant, the pattern of paresis in ALS should primarily involve those muscle groups that receive the strongest direct corticomotoneuronal (CM) innervation.
In a large cohort (N=436), we analysed retrospectively the pattern of muscle paresis in patients with ALS using the UK Medical Research Council (MRC) scoring system; we subsequently carried out two independent prospective studies in two smaller groups (N=92 and N=54).
The results indicated that a characteristic pattern of paresis exists. When pairs of muscle groups were compared within patients, the group known to receive the more pronounced CM connections was significantly weaker. Within patients, there was greater relative weakness (lower MRC score) in thumb abductors versus elbow extensors, for hand extensors versus hand flexors and for elbow flexors versus elbow extensors. In the lower limb, knee flexors were relatively weaker than extensors, and plantar extensors were weaker than plantar flexors.
These findings were mostly significant (p<0.01) for all six pairs of muscles tested and provide indirect support for the concept that ALS may specifically affect muscle groups with strong CM connections. This specific pattern could help to refine clinical and electrophysiological ALS diagnostic criteria and complement prospective clinicopathological correlation studies.
最近的一项肌萎缩侧索硬化症（ALS）神经解剖分期方案表明，皮质病变可能会扩散，作为一种网络紊乱，不仅在皮质水平，而且通过皮质传出束，包括向α运动神经元提供直接单突触输入的皮质脊髓投射。这些投射在 ALS 中优先且早期受累。如果这些发现具有临床相关性，那么 ALS 的弛缓模式应该主要涉及那些接受最强直接皮质运动神经元（CM）支配的肌肉群。
我们回顾性地使用英国医学研究理事会（MRC）评分系统分析了 436 例 ALS 患者的肌肉弛缓模式；随后，我们在两个较小的组（N=92 和 N=54）中进行了两项独立的前瞻性研究。
结果表明存在一种特征性的弛缓模式。当比较患者内的肌肉对时，已知接收更明显 CM 连接的肌肉群明显较弱。在患者内，拇指外展肌相对于肘伸肌、手伸肌相对于手屈肌以及肘屈肌相对于肘伸肌的相对无力（较低的 MRC 评分）更大。在下肢，膝屈肌相对于伸肌较弱，跖屈肌相对于跖展肌较弱。
这些发现对于所有 6 对测试肌肉都具有重要意义（p<0.01），为 ALS 可能特异性影响具有强 CM 连接的肌肉群的概念提供了间接支持。这种特定模式有助于完善临床和电生理 ALS 诊断标准，并补充前瞻性临床病理相关性研究。
