A point process analysis of electrogastric variability

The electrogastric variability is evaluated in terms of the peak-to-peak (pp) sequences. In our study we applied the Fano and Allan methodologies to pp sequences from two groups of individuals: healthy subjects and patients diagnosed with diabetes mellitus. Our goal is to determine the presence of temporal correlations in these pp time series, which are considered as point processes. We find that under healthy conditions, both Fano and Allan statistics exhibit scaling behavior with average exponents within the range of long-term correlated fluctuations, whereas for the diseased group, the average scaling exponent is close to uncorrelated dynamics. We also demonstrate that for the healthy data these scaling properties were replaced by considerably different behaviors after random shuffling of pp sequences. Moreover, our results are also corroborated by the fractal dimension method where we found that healthy dynamics is characterized by positive correlations and diseased data resemble uncorrelated fluctuations.