The electrical activity occurring during contraction of the smooth muscle cells of the corpora cavernosa can be recorded. However, interpretation of the analogous data is time-consuming. The aim of our study was to investigate whether the CC-EMG's of norma I subjects are com parable to each other and if interpretation of the CC-EMG by digitalization and Fast-Fourier-Transformation is feasible. CC-EMG's were analogously and digitally registered from 37 normal subjects during 45 minutes. Afterwards, powerspectra were made by FFT which characterize the distribution of the power above the frequency. 31/37 men showed an identical or at least a very similar electrical activity pattern on analogous registration. Needle penetration artefacts (investigated in 18 subjects) were found in 17/18 CC-EMG's during the first 20 minutes and in 1/18 during the first 40 minutes. The resulting powerspectra showed a maximum of power at a frequency of 0.3 Hertz. After this maximum, power decreases continuously by about four ten-potencies up to a frequency of 5 Hertz. More than 90% of the power occurs between 0 and 5 Hertz. Above 5 Hertz, the powerspectrum cannot be distinguished within the scope of precision of calculation from the noise. Including artefacts to the registration, power also occurs above 5 Hertz. We conclude that the registration of CC-EMG is interindividually reproducible and a computer-assisted evaluation by FTT after extraction of artefacts is feasible. Thus, interpretation of the CC-EMG signals by a computer-aided expert system seems to be practicable.
