Department of Physical Medicine and Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; VA Research Service, Rocky Mountain Regional VA Medical Center, Aurora, CO, USA.
Department of Rehabilitation Sciences, Medical University of South Carolina, Charleston, SC, USA; Muscle Morphology, Mechanics and Performance Lab, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Research Service, Washington DC VA Medical Center, Washington, DC, USA.
Mult Scler Relat Disord. 2023 Jul;75:104759. doi: 10.1016/j.msard.2023.104759. Epub 2023 May 10.
Neurologically-based muscle weakness is a common symptom in people with multiple sclerosis MS (MS), who may also exhibit muscle morphology changes and intrinsic muscle dysfunction. Diagnostic ultrasound (sonography) is a non-invasive, inexpensive, and clinically feasible method to measure muscle morphology. The purpose of this study was to investigate possible asymmetries in lower limb muscle morphology and performance in people with MS, and to assess the relationships of muscle morphology measures with individual patient characteristics, muscle performance, and functional mobility.
This cross-sectional study was conducted at the Washington, DC Veterans Affairs Medical Center. The study participants were 29 Veterans with MS (52% female, 79% African-American, 48.6 ± 11.2 years old, Mean Expanded Disability Status Scale: 3.6 ± 1.4) who completed seated knee extension isokinetic strength and power tests, functional assessments (Timed 25-Foot Walk - T25FW, 5-Times Sit-to-Stand - 5STS), and quantitative B-mode ultrasound image acquisition of the rectus femoris muscle to derive morphology measures (thickness and echogenicity). The limb with weaker knee extension strength was identified as the more-involved limb. Differences between the more and less-involved limb were quantified using a t-test for all muscle morphology and muscle performance measures. Relationships between muscle morphology and patient characteristics, muscle performance, and functional mobility were evaluated using bivariate and multivariate analyses.
The rectus femoris thickness from the more-involved limb was lower (p<0.001) than that of the less-involved limb, whereas echogenicity was not different between the two limbs (p=0.147). Rectus femoris thickness of the more-involved limb was directly related to age (r=-0.63, p<0.001), muscle strength (r=0.53, p=0.003) and power (r=0.53, p=0.003), and gait speed (r=0.42, p=0.024); whereas its echogenicity was positively associated only with muscle strength (r=-0.46, p=0.013) and power (r=-0.50, p=0.006). Together rectus femoris thickness and echogenicity of the more involved limb explained 44% and 48% of the variance in muscle strength and power, respectively (p<0.001).
This study supports the ability of sonography to measure muscle morphology in people with MS, identify asymmetries, and quantify associations with important clinical correlates. Compared with more invasive and costly alternatives, sonography is a clinically feasible, relatively low-cost tool that can be used to assess muscle morphology in people with MS. Further research is warranted to determine the potential clinical utility of sonographic measures of muscle morphology in evaluating changes due to disease progression or therapeutic interventions in this population.
神经源性肌肉无力是多发性硬化症（MS）患者的常见症状，他们可能还表现出肌肉形态变化和内在肌肉功能障碍。诊断超声（超声检查）是一种非侵入性、廉价且临床可行的方法，可用于测量肌肉形态。本研究的目的是探讨 MS 患者下肢肌肉形态和功能的可能不对称性，并评估肌肉形态测量值与个体患者特征、肌肉功能和功能移动性的关系。
这是一项在华盛顿特区退伍军人事务医疗中心进行的横断面研究。研究参与者为 29 名患有 MS 的退伍军人（52%为女性，79%为非裔美国人，48.6±11.2 岁，平均扩展残疾状况量表：3.6±1.4），他们完成了坐姿膝关节伸展等速力量和功率测试、功能评估（25 英尺步行计时测试-T25FW、5 次坐立-站起测试-5STS）以及股直肌的定量 B 型超声图像采集，以获得形态学测量值（厚度和回声）。将膝关节伸展力量较弱的肢体确定为受累较重的肢体。使用 t 检验对所有肌肉形态和肌肉功能测量值进行了受累较重和受累较轻肢体之间的差异量化。使用双变量和多变量分析评估肌肉形态与患者特征、肌肉功能和功能移动性之间的关系。
受累较重肢体的股直肌厚度较低（p<0.001），而回声无差异（p=0.147）。受累较重肢体的股直肌厚度与年龄（r=-0.63，p<0.001）、肌肉力量（r=0.53，p=0.003）和功率（r=0.53，p=0.003）以及步态速度（r=0.42，p=0.024）直接相关；而其回声仅与肌肉力量（r=-0.46，p=0.013）和功率（r=-0.50，p=0.006）呈正相关。受累较重肢体的股直肌厚度和回声分别解释了肌肉力量和功率变异的 44%和 48%（p<0.001）。
本研究支持超声检查在 MS 患者中测量肌肉形态的能力，可识别不对称性并量化与重要临床指标的关系。与更具侵入性和昂贵的替代方法相比，超声检查是一种临床可行、相对低成本的工具，可用于评估 MS 患者的肌肉形态。需要进一步研究以确定超声肌肉形态测量在评估该人群疾病进展或治疗干预引起的变化方面的潜在临床效用。
