ABSTRACT
We evaluated the surface EMG of m. rectus fem., m. tibialis ant. and m. peroneus long. using power density spectral analysis. The frequency distributions were calculated using the fast Fourier transformation for 0-250 Hz. The results of PPS patients were compared to physiological state by ranking in five to 50 Hz subranges. In cases of healthy subjects the maximum signal power falls on 50-100 Hz subrange, the minimum on 200-250 Hz. Depending on the severity of pathological symptoms, the PPS patients showed 2 different types of neuromuscular compensations. More severe pathology caused the spectrum shifts toward the higher frequencies, where the lighter cases manifest the spectrum shifts toward the lower frequencies.
Subject(s)
Muscle, Skeletal/physiopathology , Postpoliomyelitis Syndrome/physiopathology , Adult , Electromyography , Fourier Analysis , Humans , LegABSTRACT
The new electromyographic test is based on fast Fourier transformation application for analysis of global electromyograms. Specifically designed Dynalog apparatus is described. Dynalog records EMG signal and transfers it to IBM-PC. One hundred thirty-eight global electromyograms were taken from 4 muscle groups (m.rectus femoris, m.deltoideus, mm. flexores antebrachii, mm. extensores antebrachii) in healthy individuals. Standard graphs of power distribution were obtained. Physiologically, at maximum voluntary contraction, power distribution spectrum of 4 muscles display characteristic, repeatable features. The frequency distribution range is 0-250 Hz. The records obtained show an ascending part (10-50 Hz), plateau (50-100 Hz) and mildly descending one at 150 Hz, subsequently to 250 Hz.
Subject(s)
Electromyography/methods , Muscle Contraction/physiology , Muscle, Skeletal/physiology , Signal Processing, Computer-Assisted , Electromyography/instrumentation , Equipment Design , Fourier Analysis , Humans , In Vitro Techniques , Reference ValuesABSTRACT
This study deals with mathematical assessment of physiologic and pathologic EMG frequency distribution by means of ranging. Material consisted of 161 pathologic EMG (63 myogenic cases, 98 neurogenic cases). In physiologic EMG power density distribution shows the highest values between 50 and 100 Hz, the lowest between 200 and 250 Hz. From 0 to 50 Hz power density increases, from 100 to 250 Hz-decreases. In patients with muscular diseases of different etiology the EMG power density spectrum is markedly different. The highest values appear more frequently between 0 and 50 Hz, sometimes also between 100 and 150 Hz. The frequency distribution allows mainly for assessing intensity of EMG pathology; is less useful for determination of its type.
