von Walden Ferdinand, Jalaleddini Kian, Evertsson Björn, Friberg Johanna, Valero-Cuevas Francisco J, Pontén Eva
Department of Women's and Children's Health, Karolinska InstituteStockholm, Sweden.
Division of Biokinesiology and Physical Therapy, University of Southern CaliforniaLos Angeles, CA, USA.
Front Comput Neurosci. 2017 Apr 25;11:30. doi: 10.3389/fncom.2017.00030. eCollection 2017.
Children with cerebral palsy (CP) often develop reduced passive range of motion with age. The determining factor underlying this process is believed to be progressive development of contracture in skeletal muscle that likely changes the biomechanics of the joints. Consequently, to identify the underlying mechanisms, we modeled the mechanical characteristics of the forearm flexors acting across the wrist joint. We investigated skeletal muscle strength (Grippit®) and passive stiffness and viscosity of the forearm flexors in 15 typically developing (TD) children (10 boys/5 girls, mean age 12 years, range 8-18 yrs) and nine children with CP Nine children (6 boys/3 girls, mean age 11 ± 3 years (yrs), range 7-15 yrs) using the NeuroFlexor® apparatus. The muscle stiffness we estimate and report is the instantaneous mechanical response of the tissue that is independent of reflex activity. Furthermore, we assessed cross-sectional area of the flexor carpi radialis (FCR) muscle using ultrasound. Age and body weight did not differ significantly between the two groups. Children with CP had a significantly weaker (-65%, < 0.01) grip and had smaller cross-sectional area (-43%, < 0.01) of the FCR muscle. Passive stiffness of the forearm muscles in children with CP was increased 2-fold ( < 0.05) whereas viscosity did not differ significantly between CP and TD children. FCR cross-sectional area correlated to age ( = 0.58, < 0.01), body weight ( = 0.92, < 0.0001) and grip strength ( = 0.82, < 0.0001) in TD children but only to grip strength ( = 0.60, < 0.05) in children with CP. We conclude that children with CP have weaker, thinner, and stiffer forearm flexors as compared to typically developing children.
患有脑瘫（CP）的儿童通常会随着年龄增长出现被动活动范围减小的情况。据信，这一过程的决定性因素是骨骼肌挛缩的渐进性发展，这可能会改变关节的生物力学。因此，为了确定其潜在机制，我们模拟了作用于腕关节的前臂屈肌的力学特性。我们使用NeuroFlexor®仪器，对15名发育正常（TD）的儿童（10名男孩/5名女孩，平均年龄12岁，范围8 - 18岁）和9名患有CP的儿童（6名男孩/3名女孩，平均年龄11±3岁，范围7 - 15岁）的骨骼肌力量（Grippit®）以及前臂屈肌的被动刚度和粘性进行了研究。我们估计并报告的肌肉刚度是组织独立于反射活动的瞬时力学响应。此外，我们使用超声评估了桡侧腕屈肌（FCR）的横截面积。两组之间的年龄和体重没有显著差异。患有CP的儿童握力明显较弱（-65%，<0.01），FCR肌肉的横截面积较小（-43%，<0.01）。患有CP的儿童前臂肌肉的被动刚度增加了两倍（<0.05），而CP儿童和TD儿童之间粘性没有显著差异。在TD儿童中，FCR横截面积与年龄（=0.58，<0.01）、体重（=0.92，<0.0001）和握力（=0.82，<0.0001）相关，但在患有CP的儿童中仅与握力（=0.60，<0.05）相关。我们得出结论，与发育正常的儿童相比，患有CP的儿童前臂屈肌更弱、更细且更僵硬。
