- Published 1980 in Pediatric Research

The time intervals between biologic phenomena(f.e. between R-waves of ECG or respiration excursions) are not always very constant. Nevertheless such events are called "periodic".In fact the train of intervals depends on periodic and superimposed random factors(=noise).A significant task of an analysis of biologic rhythms is to separate the really periodic signals from the basic noise, and to visualize them clearly.The knowledge of the periodicity of repeated phenomena is interesting for identifying a possible functional pace-maker.It is a presuppossition to start a cross correlation for statistical investigations of the kind of interrelations of different periodic events.A suitable method to detect such a periodicity is the spectral analysis.We used it to answer the question, if the repetitive complexes(RADERMECKER complexes) in the EEG of SSPE are indeed "periodic" rhythms.After discussion of some methodological problems of autocorrelation and the variance spectra, the results of a statistic analysis of 18 tracings from seven children with SSPE are demonstrated. It could be shown, that the intervals between the typical high voltage complexes (wave bursts)are intraindividually highly constant.Over a longer time during the course of disease the lenght of intervals has a tendency to decrease.The diminution of the time span between the complexes follows a potence equation with negative exponent.The demonstrated way to analyse autocorrelations is generally useful for examinations of repeated, probably periodic biologic phenomena, which can mathematically be described as "point processes".

@article{Rabending1980IntervalAO,
title={Interval analysis of repetitive complexes in SSPE: 45},
author={G{\"{u}nter Rabending and K Jahrig and Frank Heydenreich and R Perlwitz and Markus Koch},
journal={Pediatric Research},
year={1980},
volume={14},
pages={173-173}
}