Noninvasive assessment of respiratory muscle strength and activity in Myotonic dystrophy

Objective To evaluate sensitivity/specificity of the maximum relaxation rate (MRR) of inspiratory muscles, amplitude of electromyographic activity of the sternocleidomastoid (SCM), scalene (SCA), parasternal (2ndIS) and rectus abdominis (RA) muscles; lung function and respiratory muscle strength in subjects with Myotonic dystrophy type 1 (DM1) compared with healthy subjects. Design and methods Quasi-experimental observational study with control group. MRR of inspiratory muscles, lung function and amplitude of the electromyographic activity of SCM, SCA, 2ndIS and RA muscles during maximum inspiratory pressure (PImax), maximum expiratory pressure (PEmax) and sniff nasal inspiratory pressure (SNIP) tests were assessed in eighteen DM1 subjects and eleven healthy. Results MRR was lower in DM1 group compared to healthy (P = 0.001) and was considered sensitive and specific to identify disease in DM1 and discard it in controls, as well as SNIP% (P = 0.0026), PImax% (P = 0.0077) and PEmax% ...### 研究目的 评估1型肌强直性营养不良（Myotonic dystrophy type 1, DM1）患者与健康受试者的吸气肌最大松弛率（maximum relaxation rate, MRR）、胸锁乳突肌（sternocleidomastoid, SCM）、斜角肌（scalene, SCA）、胸骨旁肌（parasternal, 2ndIS）及腹直肌（rectus abdominis, RA）的肌电活动振幅；并对比两组的肺功能与呼吸肌肌力，以明确上述指标的诊断灵敏度与特异度。 ### 设计与方法 本研究为设置对照组的类实验性观察性研究。共纳入18例DM1患者与11名健康受试者，对其吸气肌最大松弛率、肺功能，以及在最大吸气压（maximum inspiratory pressure, PImax）、最大呼气压（maximum expiratory pressure, PEmax）与鼻吸试吸气压（sniff nasal inspiratory pressure, SNIP）测试过程中，SCM、SCA、2ndIS及RA的肌电活动振幅进行了检测。 ### 研究结果 DM1组的吸气肌最大松弛率显著低于健康对照组（P=0.001），该指标具备诊断DM1的灵敏度与特异度，可有效区分DM1患者与健康对照；其诊断效能与SNIP%（P=0.0026）、PImax%（P=0.0077）及PEmax%……