Moxley Richard T, Logigian Eric L, Martens William B, Annis Chris L, Pandya Shree, Moxley Richard T, Barbieri Cheryl A, Dilek Nuran, Wiegner Allen W, Thornton Charles A
Department of Neurology, University of Rochester Medical Center, Box 673, 601 Elmwood Avenue, Rochester, New York 14642, USA.
Muscle Nerve. 2007 Sep;36(3):320-8. doi: 10.1002/mus.20822.
The aim of this study was to develop a reliable, sensitive, quantitative measure of grip myotonia and strength and to determine whether CTG repeat length is correlated with grip myotonia and with muscle strength in myotonic dystrophy type 1 (DM1). Three maximum voluntary isometric contractions (MVICs) of the finger flexors (i.e., handgrip) were recorded on 2 successive days using a computerized handgrip myometer in 29 genetically confirmed DM1 patients and 17 normals. An automated computer program calculated MVIC peak force (PF) and relaxation times (RTs) along the declining (relaxation) phase of the force recordings at 90%, 75%, 50%, 10%, and 5% of PF. Patients also underwent quantitative strength testing (QST) manual muscle testing (MMT). The patients had longer grip RTs and lower PFs than normals. RT (90% to 5%) was above the normal mean +2.5 SD in 25 (86%) patients. In DM1, prolongation of RT was mainly in the terminal (50% to 5%), rather than the initial (90% to 50%) phase of relaxation. PFs and RTs for each patient were reproducible on consecutive days. RTs were positively correlated with leukocyte CTG repeat length, whereas measures of muscle strength, such as PF, QST, and MMT, were negatively correlated with repeat length. We conclude that computerized handgrip myometry provides a sensitive, reliable measure of myotonia and strength in DM1 and offers a method to assess natural history and response to treatment.
本研究的目的是开发一种可靠、灵敏的握力性肌强直和力量的定量测量方法，并确定CTG重复长度是否与1型强直性肌营养不良症（DM1）的握力性肌强直及肌肉力量相关。使用计算机化握力计，在29例基因确诊的DM1患者和17名正常人中，连续两天记录手指屈肌（即握力）的三次最大自主等长收缩（MVIC）。一个自动化的计算机程序计算MVIC的峰值力（PF）以及在PF的90%、75%、50%、10%和5%时，力记录下降（放松）阶段的放松时间（RT）。患者还接受了定量力量测试（QST）和徒手肌力测试（MMT）。与正常人相比，患者的握力RT更长，PF更低。25例（86%）患者的RT（90%至5%）高于正常均值+2.5个标准差。在DM1中，RT延长主要在放松的末期（50%至5%），而非初期（90%至50%）阶段。每位患者的PF和RT在连续两天是可重复的。RT与白细胞CTG重复长度呈正相关，而肌肉力量指标，如PF、QST和MMT，与重复长度呈负相关。我们得出结论，计算机化握力肌测量法为DM1中的肌强直和力量提供了一种灵敏、可靠的测量方法，并提供了一种评估自然病史和治疗反应的方法。
