Intra-Rater reliability and validity of outcome measures in Myotonic Dystrophy Type 1

Objective To investigate intra-rater reliability, concurrent- and construct validity of muscle strength, balance, and functional mobility measures in individuals with non-congenital DM1. Methods Seventy-eight adults with non-congenital DM1 participated in visit 1 and 73 of the subjects participated in visit 2 separated by 1-2 weeks. The assessments consisted of muscle strength tests with Hand-Held Dynamometry (HHD) and Stationary Dynamometry in the lower limb. The balance tests comprised of Step Test, Timed Up and Go test, Feet-Together stance, Tandem-Stance, One-Leg-Stance, and modified Clinical Test of Sensory Integration and Balance on a balance platform. The functional mobility tests consisted of the 10-meter Walk Test (10mWT) and 10-times Sit-To-Stand test. Results The HHD and Stationary Dynamometry were sufficiently intra-rater reliable for most muscle groups on a group- (SEM%≤15%) and individual level (MDD95%≤30%), but HHD was most reliable. Stationary Dynamometry measured a higher torque than HHD for all extensor muscles, but for single individuals none of the devices were favored. Overall, intra-rater reliability and validity were only sufficient for the dynamic balance tests and not the static balance tests. Both functional mobility tests were sufficiently reliable and valid, but the 10mWT was most reliable. Conclusion Overall, HHD is recommended as a reliable and valid tool for single individuals and for flexor muscles on a group level. For balance assessments, the dynamic balance tests are recommended as the most valid and reliable balance tests. Both functional mobility tests are recommended for valid and reliable outcomes, but the 10mWT was superior for reliability.### 研究目标 旨在探究非先天性1型肌强直性营养不良（Myotonic Dystrophy Type 1, DM1）患者的肌肉力量、平衡能力与功能移动能力评估指标的评定者内信度、同时效标效度与结构效度。 ### 研究方法 共78名非先天性DM1成年受试者参与第1次随访，其中73名受试者在间隔1-2周后完成第2次随访。本次评估包含两类肌肉力量测试：采用手持肌力测试仪（Hand-Held Dynamometry, HHD）与下肢固定肌力测试仪开展的肌力检测。平衡测试涵盖台阶试验、计时起立行走试验（Timed Up and Go test）、并足站立试验、串联站立试验、单腿站立试验，以及平衡平台上的改良版感觉整合与平衡临床测试。功能移动能力测试则包含10米步行试验（10-meter Walk Test, 10mWT）与10次坐站试验。 ### 研究结果 手持肌力测试仪与固定肌力测试仪在群体水平（标准误百分比≤15%）与个体水平（95%最小可检测差值≤30%）下，对多数肌肉群均具备足够的评定者内信度，其中手持肌力测试仪的信度表现更优。针对所有伸肌，固定肌力测试仪测得的扭矩均高于手持肌力测试仪，但针对个体受试者而言，两款设备并无显著优劣之分。总体而言，评定者内信度与效度仅在动态平衡测试中达标，静态平衡测试未达到预设要求。两项功能移动能力测试均具备足够的信度与效度，其中10米步行试验的信度表现最优。 ### 研究结论 综上，手持肌力测试仪可作为适用于个体受试者以及群体水平屈肌测试的可靠且有效的评估工具。在平衡评估领域，动态平衡测试被推荐为效度与信度最优的平衡检测手段。两项功能移动能力测试均可产出可靠且有效的检测结果，但10米步行试验的信度更胜一筹。