The study assessed motor unit loss in muscles paralyzed by spinal cord injury (SCI) using a novel compound muscle action potential (CMAP) scan examination. The CMAP scan of the first dorsal interosseous (FDI) muscle was applied in tetraplegia (n = 13) and neurologically intact (n = 13) subjects. MScanFit was used for estimating motor unit numbers in each subject. The D50 value of the CMAP scan was also calculated. We observed a significant decrease in both CMAP amplitude and motor unit number estimation (MUNE) in paralyzed FDI muscles, as compared with neurologically intact muscles. Across all subjects, the CMAP (negative peak) amplitude was 8.01 ± 3.97 mV for the paralyzed muscles and 16.75 ± 3.55 mV for the neurologically intact muscles (p <; 0.001). The CMAP scan resulted in a MUNE of 59 ± 37 for the paralyzed muscles, much lower than 108 ± 21 for the neurologically intact muscles (p <; 0.001). No significant difference in D50 was observed between the two groups (p = 0.2). For the SCI subjects, there was no significant correlation between MUNE and CMAP amplitude, or any of the clinical assessments including pinch force, grip force, the Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP) score, and SCI duration (p > 0.05). The findings provide an evidence of motor unit loss in the FDI muscles of individuals with tetraplegia, which may contribute to weakness and other hand function deterioration. The CMAP scan offers several practical benefits compared with the traditional MUNE techniques because it is noninvasive, automated and can be performed within several minutes.

中文翻译：

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脊髓损伤后第一背侧骨间肌的 CMAP 扫描检查


该研究使用新型复合肌肉动作电位（CMAP）扫描检查评估了因脊髓损伤（SCI）而瘫痪的肌肉的运动单位损失。第一背侧骨间肌 (FDI) 的 CMAP 扫描适用于四肢瘫痪 (n = 13) 和神经完整 (n = 13) 受试者。 MScanFit 用于估计每个受试者的运动单位数量。还计算了 CMAP 扫描的 D50 值。我们观察到，与神经完好的肌肉相比，瘫痪的 FDI 肌肉的 CMAP 幅度和运动单位数估计 (MUNE) 均显着下降。在所有受试者中，瘫痪肌肉的 CMAP（负峰值）幅度为 8.01 ± 3.97 mV，神经完整肌肉的 CMAP（负峰值）幅度为 16.75 ± 3.55 mV (p <; 0.001)。 CMAP 扫描得出瘫痪肌肉的 MUNE 为 59 ± 37，远低于神经完整肌肉的 108 ± 21 (p <; 0.001)。两组之间的 D50 没有观察到显着差异 (p = 0.2)。对于 SCI 受试者，MUNE 和 CMAP 幅度或任何临床评估（包括捏力、握力、强度、敏感性和预感分级重新定义评估 (GRASSP) 评分以及 SCI 持续时间）之间不存在显着相关性 (p % 3E 0.05）。这些发现提供了四肢瘫痪患者 FDI 肌肉运动单位丧失的证据，这可能导致无力和其他手部功能恶化。与传统 MUNE 技术相比，CMAP 扫描具有多种实际优势，因为它是非侵入性、自动化的，并且可以在几分钟内完成。