Division of Rehabilitation Science, Department of Rehabilitation Medicine, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
Department of Psychiatry, University of Minnesota Medical School, Minneapolis, Minnesota, USA.
Muscle Nerve. 2021 Aug;64(2):190-198. doi: 10.1002/mus.27323. Epub 2021 Jun 9.
INTRODUCTION/AIMS: Clinical trials addressing treatments for Duchenne muscular dystrophy (DMD) require reliable and valid measurement of muscle contractile function across all disease severity levels. In this work we aimed to evaluate a protocol combining voluntary and evoked contractions to measure strength and excitability of wrist extensor muscles for safety, feasibility, reliability, and discriminant validity between males with DMD and controls.
Wrist extensor muscle strength and excitability were assessed in males with DMD (N = 10; mean ± standard deviation: 15.4 ± 5.9 years of age), using the Brooke Upper Extremity Rating Scale (scored 1-6), and age-matched healthy male controls (N = 15; 15.5 ± 5.0 years of age). Torque and electromyographic (EMG) measurements were analyzed under maximum voluntary and stimulated conditions at two visits.
A protocol of multiple maximal voluntary contractions (MVCs) and evoked twitch contractions was feasible and safe, with 96% of the participants completing the protocol and having a less than 7% strength decrement on either measure for both DMD patients and controls (P ≥ .074). Reliability was excellent for voluntary and evoked measurements of torque and EMG (intraclass correlation coefficient [ICC] over 0.90 and over 0.85 within and between visits, respectively). Torque, EMG, and timing of twitch-onset measurements discriminated between DMD and controls (P < .001). Twitch contraction time did not differ significantly between groups (P = .10).
Findings from this study show that the protocol is a safe, feasible, reliable, and a valid method to measure strength and excitability of wrist extensors in males with DMD.
简介/目的：针对杜氏肌营养不良症（DMD）治疗的临床试验需要可靠且有效的测量所有疾病严重程度水平的肌肉收缩功能。在这项工作中，我们旨在评估一种结合自愿和诱发收缩的方案，以测量腕伸肌的力量和兴奋性，评估其安全性、可行性、可靠性和 DMD 男性与对照组之间的鉴别效度。
使用 Brooke 上肢评定量表（评分 1-6）评估 10 名 DMD 男性（平均 ± 标准差：15.4 ± 5.9 岁）和 15 名年龄匹配的健康男性对照者（15.5 ± 5.0 岁）的腕伸肌力量和兴奋性。在两次就诊时，在最大自愿和刺激条件下分析扭矩和肌电图（EMG）测量值。
多次最大自愿收缩（MVC）和诱发 twitch 收缩的方案是可行且安全的，96%的参与者完成了方案，并且在 DMD 患者和对照组中，两种措施的力量下降均小于 7%（P≥.074）。扭矩和 EMG 的自愿和诱发测量的可靠性非常好（组内相关系数 [ICC]分别超过 0.90 和 0.85，分别在就诊内和就诊间）。扭矩、EMG 和 twitch-onset 测量的时间可区分 DMD 和对照组（P<.001）。Twitch 收缩时间在两组间无显著差异（P=0.10）。
本研究的结果表明，该方案是一种安全、可行、可靠且有效的方法，可测量 DMD 男性腕伸肌的力量和兴奋性。
