The endplate potential (EPP) component can be extracted from the surface EMG using a digital filter. The extracted EPP shows oscillation with a frequency of about 30 Hz.
1. Preparation of EMG electrodes
2. EMG recording
3. EPP extraction and observation of its features
4. EMG recording results
Figure 1a: Shown here is a schematic of the eight sites along the masseter muscle that were recorded from.
Figure 1b: We see a sample of the monopolar EMGs recorded simultaneously from the sites over the masseter muscle in response to quick gum clenching on the ipsilateral side. The EPP component was extracted using a high-cut digital filter with a cut-off frequency of 10Hz, which is superimposed on each raw EMG. In this trial, the most negative deflection was observed in traces-5 and -6 and the polarity changed across trace-3.
Figure 1c: When the cut-off frequency of the high-cut digital filter was set to 30Hz, the slow wave exhibited an oscillation. Its phase also shifted across trace 3, where the polarity of the 10Hz-filtered EPP wave changed. The interval between neighboring positive peaks of the oscillation was measured. In this subject, the average inter-peak interval was 31.7 ± 6.5 msec over 16 recordings.
I would like to offer great thanks to David Carlson, Professor of English at Matsumoto Dental University, for his kind support in writing this report. I would also like to thank Tadafumi Adachi, a seminarist in our laboratory, for his compliance as a subject in this investigation.
Material Name | Type | Company | Catalogue Number | Comment |
---|---|---|---|---|
Analogue filter | Nihon Kohden | MEG6100 | pre-,main-amplifier | |
A/D converter | National Instruments | PCI-MIO-16E-4 | PCI board for computer | |
Connection interface | National Instruments | BNC-2090 | 8ch BNC adaptor | |
Disc electrodes | Nihon Kohden | NS-11 | Ag/AgCl (Φ8mm) | |
Electrode past | Sanshin | SA-5 | Semi-fluid carbon past | |
LabVIEW (Digital filter) | National Instruments | V. 8.5 | Programming language | |
Chewing gum | Lotte | Green gum | Test food in clenching |