We previously reported a new quantitative analysis of single‐channel surface electromyography (EMG), the “clustering index method” (CI method), in the tibialis anterior muscle, which achieved sufficiently good sensitivity to detect neurogenic or myogenic abnormalities. The window width is a fundamental parameter of the CI method, and was arbitrarily set at 15 ms in that study. In this study, we searched for the most appropriate window width using expanded patient data. The data from our previous study were reanalyzed, and new patients were enrolled. Window width in the CI method was changed from 5 to 27.5 ms with a step of 2.5 ms. For each window width, Z‐score values of individual subjects were calculated and the diagnostic yield was investigated. We enrolled 67 controls, 29 subjects with neurogenic disorders, and 39 with myogenic disorders. When the window width was set at 22.5 ms, the highest sensitivity was achieved both for neurogenic (97%) and myogenic (72%) disorders, with a specificity of 97%. Seven of 10 patients with inclusion body myositis were also abnormal. Reliable results were obtained by collecting 15 epochs per subject. There are two conflicting effects that appear to be best balanced at a window width of 22.5 ms: a wider width decreases the chance that a motor unit potential (MUP) is divided into two adjacent windows, and a narrower width reduces the possibility that an MUP firing at a low‐frequency is counted twice by the differential sequences. CI is promising as a non‐invasive method to diagnose neuromuscular disorders.

中文翻译：

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胫骨前肌的“聚类指数法”的适当窗口宽度

我们之前曾报道过一种新的定量分析胫骨前肌的单通道表面肌电图（EMG），即“聚类指数法”（CI法），该方法具有足够好的灵敏度来检测神经源性或肌源性异常。窗口宽度是CI方法的基本参数，在该研究中任意设置为15 ms。在这项研究中，我们使用扩展的患者数据搜索了最合适的窗口宽度。重新分析了我们先前研究的数据，并招募了新患者。CI方法中的窗口宽度从5毫秒更改为27.5毫秒，步长为2.5毫秒。对于每个窗口宽度，计算单个受试者的Z分数，并研究诊断率。我们招募了67名对照，29名神经源性疾病和39名肌源性疾病。当窗口宽度设置为22.5 ms时，神经源性疾病（97％）和肌源性疾病（72％）的灵敏度最高，特异性为97％。10名包涵体肌炎患者中有7名也异常。通过收集每个受试者15个时期来获得可靠的结果。在22.5 ms的窗口宽度下，似乎有两种相互矛盾的效果可以达到最佳平衡：更宽的宽度减少了将电机单元电势（MUP）分为两个相邻窗口的机会，而更窄的宽度则减少了MUP的可能性低频触发由差分序列计算两次。CI有望作为一种非侵入性的方法来诊断神经肌肉疾病。特异性为97％。10名包涵体肌炎患者中有7名也异常。通过收集每个受试者15个时期来获得可靠的结果。在22.5 ms的窗口宽度下，似乎有两种相互矛盾的效果可以达到最佳平衡：更宽的宽度减少了将电机单元电势（MUP）分为两个相邻窗口的机会，而更窄的宽度则减少了MUP的可能性低频触发由差分序列计算两次。CI有望作为一种非侵入性的方法来诊断神经肌肉疾病。特异性为97％。10名包涵体肌炎患者中有7名也异常。通过收集每个受试者15个时期来获得可靠的结果。在22.5 ms的窗口宽度下，似乎有两种相互矛盾的效果可以达到最佳平衡：更宽的宽度减少了将电机单元电势（MUP）分为两个相邻窗口的机会，而更窄的宽度则减少了MUP的可能性低频触发由差分序列计算两次。CI有望作为一种非侵入性的方法来诊断神经肌肉疾病。较宽的宽度减少了将电机单位电势（MUP）分成两个相邻窗口的机会，而较窄的宽度则减少了通过差分序列对以较低频率触发的MUP计数两次的可能性。CI有望作为一种非侵入性的方法来诊断神经肌肉疾病。较宽的宽度减少了将电机单位电势（MUP）分成两个相邻窗口的机会，而较窄的宽度则减少了通过差分序列对以较低频率触发的MUP计数两次的可能性。CI有望作为一种非侵入性的方法来诊断神经肌肉疾病。