Université de Lyon, F-42023, Saint-Etienne, France.
Clin Neurophysiol. 2011 Apr;122(4):842-7. doi: 10.1016/j.clinph.2010.10.028. Epub 2010 Nov 18.
We investigate the influence that inguinal fat has on maximal quadriceps response to femoral nerve magnetic stimulation.
Vastus lateralis M-wave amplitude and quadriceps twitch peak torque were measured (i) in lean and overweight subjects and (ii) when slices of pig fat ranging from 2 to 18 mm in thickness were placed between the coil and the nerve.
In overweight group, the maximal response could not be elicited when intensity was ≤90% and ≤85% of maximal power for twitch torque and M-wave amplitude, respectively. The maximal response was obtained at 80% of maximal power in the lean group. Negative correlations between relative twitch torque changes and inguinal thickness were observed. Fat thickness altered quadriceps response at 14 mm and 8 mm in the lean and overweight groups, respectively.
The capacity of femoral nerve magnetic stimulation to deliver supramaximal stimulation is altered when fat thickness below the coil increases.
Special caution should be taken by clinicians when overweight or obese subjects are tested using femoral nerve magnetic stimulation.
我们研究了腹股沟脂肪对股神经磁刺激时最大股四头肌反应的影响。
在瘦和超重受试者中，测量了股外侧肌 M 波幅度和股四头肌单次收缩峰值扭矩（i）；并在将厚度为 2 至 18 毫米的猪脂肪片置于线圈和神经之间时测量了上述参数（ii）。
在超重组中，当刺激强度分别为最大单次收缩扭矩和 M 波幅度的 90%和 85%时，无法引出最大反应。在瘦组中，最大反应发生在最大力量的 80%。相对单次收缩扭矩变化与腹股沟厚度之间存在负相关。在瘦组和超重组中，脂肪厚度分别为 14 毫米和 8 毫米时，改变了股四头肌的反应。
当线圈下方的脂肪厚度增加时，股神经磁刺激传递超强刺激的能力会发生改变。
当使用股神经磁刺激对超重或肥胖受试者进行测试时，临床医生应特别小心。
