級内相関係数を用いた横隔膜筋音図信号の再現性評価と最適導出位置の検討

摘要

The mechanomyogram (MMG) is a recording of small vibration on the body surface due to lateral expansion of contracting muscle fibers. The present investigation aimed to determine appropriate recording area in measuring the MMG from diaphragm and to clarify its reliability using intraclass correlation coefficient (ICC) for promoting clinical application of the MMG. A single twitch contraction of diaphragm was elicited by applying electric stimulation to phrenic nerve. The MMG and electromyogram (EMG) were recorded at six different areas over the surface of thorax, i. e., each two positions on 7th to 9th intercostal space. Both MMG and EMG demonstrated excellent reliability in all the recording areas with mean ICC of 0.973. The significantly greater amplitude in both signals was observed on body surface at the intersection of the 8th or 9th intercostal space and the sagittal line on the 9th rib margin. The findings suggest that the diaphragmatic MMG and EMG are derived most appropriately from these surface areas of thorax.