Natus Medical Inc, Hopewell Junction, New York, USA; Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
Clin Neurophysiol. 2022 Jul;139:119-127. doi: 10.1016/j.clinph.2022.04.011. Epub 2022 Apr 26.
The compound muscle action potential (CMAP) scan is useful to study motor unit (MU) loss. It is of interest to develop simple measurements of the scan.
CMAP scan recordings were performed in the abductor pollicis brevis muscle of 20 control subjects and 26 patients with amyotrophic lateral sclerosis (ALS). They were analyzed using two new measurements called Step index (STEPIX) reflecting the number of steps, and Amplitude index (AMPIX) for amplitude of these steps.
In control subjects, STEPIX ranged from 71 to 172 while AMPIX was 78-158 µV. In ALS patients STEPIX was reduced and AMPIX was increased. The degree of change in STEPIX and AMPIX varied among patients reflecting the success or failure of reinnervation. Follow up studies in 9 muscles demonstrated reduced STEPIX and increased AMPIX despite minimal change in the CMAP.
STEPIX and AMPIX are deterministic measurements of the CMAP scan made using a spreadsheet program. STEPIX and AMPIX can be inferred as indices for the number of motor units and their size, and demonstrate the expected pattern in ALS patients.
The new algorithm for CMAP scan analysis may be useful to study disease progression in patients with ALS.
复合肌肉动作电位（CMAP）扫描可用于研究运动单位（MU）的丢失。开发扫描的简单测量方法很有意义。
对 20 名对照受试者和 26 名肌萎缩侧索硬化症（ALS）患者的拇短展肌进行 CMAP 扫描记录。使用两种新的测量方法，即反映步长数量的步长指数（STEPIX）和这些步长的幅度的幅度指数（AMPIX）进行分析。
在对照组中，STEPIX 范围为 71 至 172，而 AMPIX 为 78-158µV。在 ALS 患者中，STEPIX 降低，AMPIX 增加。STEPIX 和 AMPIX 的变化程度在患者之间有所不同，反映了再支配的成功或失败。对 9 块肌肉的随访研究表明，尽管 CMAP 几乎没有变化，但 STEPIX 降低，AMPIX 升高。
STEPIX 和 AMPIX 是使用电子表格程序对 CMAP 扫描进行的确定性测量。STEPIX 和 AMPIX 可以作为运动单位数量及其大小的指标，并在 ALS 患者中表现出预期的模式。
CMAP 扫描分析的新算法可能有助于研究 ALS 患者的疾病进展。
