在这项研究中,我们旨在研究重症肌无力(MG)患者同心针抖动研究的平均连续差(MCD)的分散性及其对MG诊断敏感性的影响。
一百五十三个病人,包括76名MG患者和77名可能患有MG的对照组,他们后来接受了另一次诊断,对额肌进行了刺激的同心针抖动研究。MCD的意思是,标准偏差(SD),并计算变异系数(CV)。使用受试者工作特征(ROC)分析确定诊断灵敏度和特异性。
MG患者表现出明显更大的MCD平均值(MG:对照,26.3μs;13.5μs[中位数];P<.0001),MCDSD(MG:控制,12.8μs;5.1μs[中位数];P<.0001),和MCDCV(MG:控制,46.1;37.5[中位数];P<.001)比没有MG的人。SD的ROC曲线显示曲线下面积较大(0.88),和7.2μs的截止值,这是通过最大尤登指数计算的,对MG表现出较高的诊断敏感性(86%)。MCD组合意味着,异常值,和SD标准显示出比常规标准(82%)更高的灵敏度(88%),以降低特异性为代价。5例MCD均值正常、MCD异常SD的MG患者仅有眼部症状。
在MG患者中,通过MCDSD大于7.2μs测量的MCD色散显着增加,并且可能是诊断MG时异常抖动的有用量度,特别是用于识别轻度疾病的患者。
In this study we aimed to investigate the dispersion of mean consecutive difference (MCD) of concentric needle jitter studies of patients with myasthenia gravis (MG) and its effect on diagnostic sensitivity for MG.
One hundred fifty-three patients, including 76 patients with MG and 77 controls with possible MG who later received another diagnosis, underwent stimulated concentric needle jitter studies of the frontalis muscle. MCD mean, standard deviation (SD), and coefficient of variation (CV) were calculated. Diagnostic sensitivity and specificity were determined using receiver operating characteristic (ROC) analyses.
MG patients showed a significantly greater MCD mean (MG: control, 26.3 μs; 13.5 μs [median]; P < .0001), MCD SD (MG: control, 12.8 μs; 5.1 μs [median]; P < .0001), and MCD CV (MG: control, 46.1; 37.5 [median]; P < .001) than those without MG. An ROC curve of SD showed a large area under the curve (0.88), and a cut-off value of 7.2 μs, which was calculated by maximum Youden index, exhibited high diagnostic sensitivity (86%) for MG. Combined MCD mean, outliers, and SD criteria showed higher sensitivity (88%) than conventional criteria alone (82%), at the expense of lower specificity. Five MG patients with normal MCD mean and abnormal MCD SD had only ocular symptoms.
The dispersion of MCD as measured by MCD SD greater than 7.2 μs is significantly increased in patients with MG and may be a useful measure of abnormal jitter in the diagnosis of MG, especially for identifying patients with mild disease.