Neuroanatomical Models of Muscle Strength and Relationship to Ambulatory Function in Spinal Muscular Atrophy.
Neuroanatomical Models of Muscle Strength and Relationship to Ambulatory Function in Spinal Muscular Atrophy.
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DOI：
10.3233/jnd-200550
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发表时间：
2020
影响因子：
3.3
通讯作者：
Montes, Jacqueline
中科院分区：
文献类型：
--
作者：
Rodriguez-Torres, Rafael;Fabiano, Julia;Goodwin, Ashley;Rao, Ashwini K.;Kinirons, Stacy;De Vivo, Darryl;Montes, Jacqueline
患有脊髓性肌萎缩症（SMA） III的个体可以独立行走，但会出现肌肉无力、步态障碍和疲劳。虽然SMA影响近端肌肉多于远端肌肉，但选择性肌肉无力的特征模式尚未得到解释。目前提出了两种理论：1)脊髓运动神经元的位置；2)节段性神经支配的差异。确定解释SMA个体选择性肌无力的神经解剖学模型，并评估这些模型与行走功能的关系。数据来自23名流动SMA参与者（78.2%男性），年龄10-56岁，参加了两项临床研究（NCT01166022, NCT02895789）。强度采用医学研究委员会（MRC）评分进行评估；通过6分钟步行测试（6 MWT）测量行走功能。确定了三个模型，并使用Pearson相关系数和线性回归评估了它们之间的关系。所有模型均显示强度与功能呈正相关（p < 0.02）。线性回归显示，由下腰椎和骶节神经支配的肌肉组成的3B模型解释了6 MWT表现中67%的变异性（β = 0.670, p = 0.003）。下腰椎和骶节神经支配的肌肉，即髋伸肌、髋外展肌、膝关节屈肌和踝关节背屈肌，与更大的运动功能相关，并预示着更大的运动功能。肌肉无力的神经解剖学模式可能有助于更好地了解疾病机制，并使靶向治疗成为可能。
Individuals with spinal muscular atrophy (SMA) III walk independently, but experience muscle weakness, gait impairments, and fatigue. Although SMA affects proximal more than distal muscles, the characteristic pattern of selective muscle weakness has not been explained. Two theories have been proposed: 1) location of spinal motor neurons; and 2) differences in segmental innervation. To identify neuroanatomical models that explain the selective muscle weakness in individuals with SMA and assess the relationship of these models to ambulatory function. Data from 23 ambulatory SMA participants (78.2% male), ages 10–56 years, enrolled in two clinical studies (NCT01166022, NCT02895789) were included. Strength was assessed using the Medical Research Council (MRC) score; ambulatory function was measured by distance walked on the 6-minute walk test (6 MWT). Three models were identified, and relationships assessed using Pearson correlation coefficients and linear regression. All models demonstrated a positive association between strength and function, (p < 0.02). Linear regression revealed that Model 3B, consisting of muscles innervated by lower lumbar and sacral segments, explained 67% of the variability observed in 6 MWT performance (β = 0.670, p = 0.003). Muscles innervated by lower lumbar and sacral segments, i.e. hip extensors, hip abductors, knee flexors and ankle dorsiflexors, correlated with and predicted greater ambulatory function. The neuroanatomical patterns of muscle weakness may contribute to a better understanding of disease mechanisms and enable delivery of targeted therapies.