Background

Duchenne muscular dystrophy is an X-linked muscle disease caused by dystrophin absence. Muscle weakness is a major determinant of the gait impairments in patients with Duchenne muscular dystrophy and it affects lower limbs more often than upper limbs. Monitoring progression of motor symptoms is key to plan treatments for prolonging ambulation.

Methods

The progression of gait impairment in a group of ten patients with Duchenne muscular dystrophy was observed longitudinally three times over a period of 2 years by computerized gait analysis system. Spatio-temporal parameters of gait, and variability indicators were extracted from kinematics, while lower limb muscles coactivation were measured at the baseline and at each follow-up evaluation. The 6-min walk test was used to evaluate functional capacity at each time session.

Findings

We found a significant increase in stride width and in both stride width and stride length variability at the 1-and 2-year follow-up evaluations. Furthermore, significant higher values in proximal muscle coactivation and significant lower values in both distal muscle coactivation and functional capacity were found at the 2-year follow-up evaluation. Significant negative correlations between muscle coactivation at proximal level and functional capacity and between muscle coactivation at distal level and gait variability were observed.

Interpretation

Our findings suggest that patients with Duchenne muscular dystrophy exhibit decline in functional capacity after 2 years from the baseline. Moreover, to cope with disease progression, patients try to maintain an effective gait by changing the balance dynamic strategies (i.e. increase in proximal muscle coactivation) during the course of disease.

中文翻译：

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患有Duchenne肌营养不良症的儿童的肌肉共激活和步态变化的进展：一项为期2年的随访研究。

背景

Duchenne肌营养不良症是由于缺乏肌营养不良蛋白而引起的X链肌病。肌肉无力是杜氏肌营养不良患者步态障碍的主要决定因素，它影响下肢的频率高于上肢。监测运动症状的进展是计划延长下床活动治疗的关键。

方法

通过计算机化步态分析系统，在10年的时间里，对10例Duchenne肌营养不良症患者的步态障碍的进展进行了3次纵向观察。从运动学中提取步态的时空参数和变异性指标，同时在基线和每次随访评估中测量下肢肌肉的共激活。6分钟步行测试用于评估每个时间段的功能能力。

发现

在1年和2年的随访评估中，我们发现步幅，步幅和步幅变异性均显着增加。此外，在两年的随访评估中，发现近端肌肉共激活显着较高的值，而远端肌共激活和功能能力均显着较低的值。观察到在近端水平的肌肉共激活与功能能力之间以及在远端水平的肌肉共激活与步态变异之间存在显着的负相关。

解释

我们的发现表明，患有杜氏肌营养不良症的患者距基线2年后，其功能能力下降。此外，为了应对疾病的进展，患者尝试通过在疾病过程中改变平衡动态策略（即增加近端肌肉共激活）来保持有效的步态。