積分筋電図とその周波数分析（主として「筋力」の判定について）

Integrated Electromyogram and its Frequency-Analysis

　Ⅰ．緒言

　いわゆる「筋力」のような総合された筋機能の現れを，筋電図から観察しようとする場合には，多数のmotor unitの活動電位の総合された複雑な筋電図波形を通じて，全体的な筋活動状態を観察する方法即ち，周波数分析法或いは積分値による分析法がよくとられる。

　ここで先ず周波数分析法については，古くはPiper^18）（1919）の筋疲労と共に主周波数が減少するという報告に続いて，Cobb, Forber^4）（1923），加藤^13）（1931）等の同様な報告があり，最近ではWalton^24）（1952），Fex, Krakau^6）（1957）等によつてAudio-frequency Spectrometerによる分析が行われている。

　The relationship between the electrical activity and the tension of the muscle has been investigated on normal subjects. EMG was picked up mainly from the m. biceps brachii by surface electrods, and it was analysed by several methods of analysis.

　1) In case of monopolar lead, EMG was disturbed with propagation of the potential of other muscles, and was influenced by EKG. Therefore bipolar lead under certain conditions was applied in the present experiment.

　2) In the comparison of the filter type integrator and the condenser discharge type one, the latter showed superiority in the linearity of its frequency characteristic.

　3) In the mathematical analysis, the amplitude of each components showed a large dispersivity and it was not suitable for EMG analysis for its tedious procedure.

　4) In the analysis by means of Sonagraph, smaller dispersivity than that of the mathematical analysis was shown by wide band of 19 cycles.

　5) In the analysis of the EMG by means of Sonagraph, there was a tendency that the components of 20 and 40 cycle increased and those of above 60 cycle decreased in amplitude and the average integral of the EMG increased in amplitude and the average integral of the EMG increased when subjects felt fatigue following a sustained work.