Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA 02215, United States.
Clin Neurophysiol. 2013 Feb;124(2):400-4. doi: 10.1016/j.clinph.2012.07.013. Epub 2012 Aug 20.
Recent developments in electrical impedance myography (EIM) have led to the use of handheld electrode arrays (HEAs) for data acquisition. Although preferable for several reasons, this approach tends to be more affected by subcutaneous fat (SF) than the original approach in which the impedance-measuring electrodes are widely spaced. In this study, we seek to identify the EIM parameter least impacted by subcutaneous fat (SF) when using an HEA.
18 normal subjects underwent 50 kHz EIM and ultrasound of the medial gastrocnemius muscles on the dominant side. Coefficients of determination (R(2) values) were calculated for each of the three major EIM variables (reactance, resistance, and phase) and SF thickness.
For both resistance and phase, a strong relationship to SF thickness was observed (R(2) = 0.64 and R(2) = 0.70, respectively, p < 0.001 for both). In contrast, for reactance, the relationship was non-significant, with R(2) = 0.07, p = 0.30.
Unlike resistance and phase, both of which are highly impacted by SF thickness, the reactance shows no significant relationship.
Future clinical studies employing HEA's to perform EIM should evaluate alterations in reactance in addition to those in resistance and phase.
最近，电阻抗肌电图（EIM）的发展使得手持电极阵列（HEA）可用于数据采集。尽管出于多种原因，这种方法更可取，但与原始方法相比，它往往更容易受到皮下脂肪（SF）的影响，原始方法中，阻抗测量电极的间距较大。在这项研究中，我们试图确定使用 HEA 时受皮下脂肪（SF）影响最小的 EIM 参数。
18 名正常受试者在优势侧接受 50 kHz 的 EIM 和内侧比目鱼肌的超声检查。为三个主要的 EIM 变量（电抗、电阻和相位）和 SF 厚度中的每一个计算决定系数（R² 值）。
对于电阻和相位，都观察到与 SF 厚度的强相关性（R²=0.64 和 R²=0.70，均为 p<0.001）。相比之下，电抗的相关性不显著，R²=0.07，p=0.30。
与电阻和相位不同，电抗不受 SF 厚度的高度影响，两者均与电抗无显著关系。
未来使用 HEA 进行 EIM 的临床研究应评估电抗的变化，除了电阻和相位的变化。
