[Electromyographic study on the external urethral sphincter of the male--power spectrum analysis with fast Fourier transformation].
In 23 male patients, the electrical activity of external urethral sphincter muscle was sampled before examination of cystometry (Rest), at first desire to void (FDV), maximum desire to void (MDV) and during urination (Void) by means of electromyography (EMG). Sampling time of each event was 2400 msec. The electrical activity was amplified with a lower limiting frequency of 20 Hz and an upper limiting frequency of 10000 Hz, and recorded on magneto-optical desk. Spectra were obtained using a Hamming window. The action potential of the muscle was quantitatively analyzed and power spectrum of the needle EMGs were analyzed from the magneto-optical disk by a spectrum analyzer using fast Fourier transformation (FFT, Sande-Tukey method). From each power spectrum, mean power frequency (MPF) was obtained from a calculator connected to the spectrum analyzer. Twenty three patients were divided into three groups as follows: 8 patients without any neurological abnormality (normal group), 7 patients with neurogenic bladder showing detrusor-sphincter-dyssynergia (DSD+ group) and 8 patients with neurogenic bladder without detrusor-sphincter-dyssynergia (DSD- group). The results obtained were as follows: 1) The motor unit potentials at Rest had the mean amplitude of 210 +/- 59.4 microV, 329.3 +/- 157.1 microV and 177.6 +/- 132.8 microV in normal group, DSD+ group and DSD- group, respectively. The mean duration were 4.3 +/- 0.2 msec, 5.9 +/- 1.9 msec, and 7.3 +/- 4.5 msec., respectively. The mean phases were 2.8 +/- 0.6, 2.8 +/- 0.5 and 2.5 +/- 0.3, respectively. Statistically there was no difference in amplitude, duration and phase among three groups. 2) In normal group, the power over than -20 dB was distributed from 150 to 220 Hz windows at Rest and FDV. The needle EMGs at MDV showed interference pattern and the power increased over -20 dB in all windows. The power of high frequency area relatively increased. The action potential of the muscle disappeared during urination and the power also disappeared. The average MPF was 103 Hz, 102 Hz, 150 Hz and 98 Hz at Rest, FDV, MDV and Void, respectively. 3) In DSD+ group, the needle EMGs showed interference pattern in MDV and Void, and the power increased only in low frequency area. The average MPF was 104 Hz, 105 Hz, 114 Hz and 120 Hz at Rest, FDV, MDV and Void, respectively. 4) Because of damage to nerves, the action potential of the muscle was difficult to obtain from 3 patients of DSD- group, and the power was not demonstrated.(ABSTRACT TRUNCATED AT 400 WORDS)
Mizuo
T
T
Department of Urology, Tokyo Rosai Hospital.
Suzuki
M
M
Oya
K
K
Kura
N
N
Terao
T
T
D000328:Adult; D000368:Aged; D004576:Electromyography; D005583:Fourier Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D014521:Urethra / Q000502:physiology* / Q000503:physiopathology; D001743:Urinary Bladder / Q000502:physiology; D001750:Urinary Bladder, Neurogenic / Q000503:physiopathology; D014554:Urination