Bulea Thomas C, Guth Amanda, Sarkar Nathan, Gravunder Andrew, Hodsdon Bonnie, Farrell Kathleen, Comis Leora E, Parks Rebecca, Shimellis Hirity, Ndege Vanessa, Ho Pei-Shu, Mankodi Ami
Functional and Applied Biomechanics Section, Rehabilitation Medicine Department, National Institutes of Health Clinical Center, Bethesda, MD, United States of America.
Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland, United States of America.
Neuromuscul Disord. 2022 Apr;32(4):321-331. doi: 10.1016/j.nmd.2022.02.005. Epub 2022 Feb 14.
Grip myotonia and weakness are attractive treatment response biomarkers in clinical trials of myotonic dystrophy type 1 (DM1). There is a need to develop simple, patient-friendly and reproducible methods of quantifying grip myotonia in multisite trial settings. We designed a HandClench Relaxometer (HCR) that measures grip myotonia and strength. In contrast with the existing quantitative myometry (QMA) setup, the HCR is portable, economical, can be used with any laptop and generates automated command prompts. We demonstrate the feasibility and reliability of HCR device in twenty DM1 individuals and ten age-matched controls; patients returned for follow up within two months. The device showed excellent day to day reproducibility (ICC >0.80) in patients. The HCR device detected myotonia in milder muscle disease and measured longer myotonia duration than QMA indicating enhanced sensitivity for quantifying myotonia in DM1. The reaction time to the relax but not squeeze command was delayed and showed warm up similar to myotonia in DM1. HCR outcomes were correlated with key pinch strength, hand dexterity test, and fat replacement in the MRI of the long finger flexor muscles. Use of the HCR is warranted for grip myotonia and strength measurements in longitudinal observational and interventional studies of DM1.
在1型强直性肌营养不良（DM1）的临床试验中，握力性肌强直和肌无力是颇具吸引力的治疗反应生物标志物。在多中心试验环境中，需要开发简单、对患者友好且可重复的方法来量化握力性肌强直。我们设计了一种手部紧握松弛计（HCR），用于测量握力性肌强直和力量。与现有的定量肌动测量法（QMA）设置不同，HCR便于携带、经济实惠，可以与任何笔记本电脑配合使用，并能生成自动命令提示符。我们在20名DM1患者和10名年龄匹配的对照者中证明了HCR设备的可行性和可靠性；患者在两个月内返回进行随访。该设备在患者中显示出出色的每日可重复性（组内相关系数>0.80）。HCR设备在较轻的肌肉疾病中检测到了肌强直，并且测量到的肌强直持续时间比QMA更长，这表明其在量化DM1中的肌强直方面具有更高的灵敏度。对放松命令而非挤压命令的反应时间延迟，并且显示出与DM1中的肌强直类似的热身现象。HCR的结果与关键捏力、手部灵活性测试以及长指屈肌MRI中的脂肪替代相关。在DM1的纵向观察性研究和干预性研究中，有必要使用HCR来测量握力性肌强直和力量。
