Development of Evaluation of Swallowing Using Neck Electrical Impedance

我们提出了一种新的吞咽障碍评估方法——阻抗咽喉术（IPG），在IPG的测量方法中，采用了基于正弦恒流（50 kHz, 0.5 mA）的四电极技术，该技术几乎不受皮肤阻抗的影响。用同步整流法测量被评估部分的等效串联电阻作为阻抗。考虑到IPG的以下频率特性，确定低通滤波器的截止频率为25hz。电极为直径为10mm的无极化Ag-AgCl皮肤表面型。根据被测部件的位置和阻抗的变化情况，确定电极的位置。电流电极的位置是以下两条直线的交汇点。下颌骨角与下颌骨髁突之间的一条线。另一条线与下颌骨平行这条线要求电极的粘接项圈在颈部和下巴之间的边界上。电位电极的位置与下颌骨平行，在电流电极的位置内。电极之间的距离为25mm。受试者坐在椅子上，嘴里含着10cc的水。椅背的角度为75度，阻抗的变化是由于食道尖角随食物丸的运动而发生变化。我们发现主阻抗下降的周期与咽部下降的周期一致。正常受试者的吞咽期可通过IPG进行划分。大于10hz的频率分量的功率谱密度小于- 60db，从这个角度来看，吞咽运动信息几乎包含了小于10hz的频率分量。该方法可用于吞咽障碍的诊断。我们未来的研究是利用正常人和患者的数据来研究考虑IPG模式的诊断。

We have proposed impedance pharyngograpy (IPG) which is a new evaluation method of swallowing disorders, In the measuring method of IPG is used the four-electrode technique, which is hardly influenced by skin impedance, based on sinusiodal constant current (50 kHz, 0.5 mA). The equivalent series resistance of the evaluated part is measured as impedance using synchronous rectified method. Considering the below mentioned frequency characteristics of IPG, the cut-off frequency of low pass filter is decided as 25 Hz. The electrodes are non-polarization Ag-AgCl skin surface type of 10 mm diameter.We decided the locations of electrodes, considering the conditions about the location of the measured part and change value of impedance. The location of current electrodes is a point of meeting the following two straight lines. The one line joins angle of mandible and condyloid process of mandible. The other line is parallel to mandible and this line is required that adhesive collars for electrodes is on the border between neck and chin. The location of potential electrodes is on line parallel to mandible and inside of the location current ones. The distance between electrodes is 25 mm. A subject sits on a chair and keeps 10 cc water in his mouth. The angle of the chair back is 75 deg.The changes of impedance is caused by the changes of the sharp of esophagus with movement of the bolus of food. We found that the period of main impedance decrease was the same period of pharynx. The phase of swallowing in normal subject can be divided by IPG.The power spectrum density in frequency component of more than 10 Hz is less than -60 dB, From this view point one may say that information about swallowing movement almost includes frequency component of less than 10 Hz.This method can be applied for diagnosis of swallowing disorders. Our future study is to investigate diagnosis considering patterns of IPG using normals and patients data.