Computer analysis of manometric recordings. A study of overnight rectal activity in normal children

To read and analyze manometric tracings from selected biological systems, a computer program was produced using low cost personal computer hardware. The program contains facilities for automatic scoring of contractions, intercontractile intervals (modality) and frequency analysis. This report concerns analysis of two overnight rectal motility recordings in 11 normal teenagers. After A/D conversion of data the developed software offers a set of options i.e. automatized scoring of contraction, detection of intervals between contractions and analytical tools such as histographic presentation of data, and presentation in the time domain. The A/D conversion time and computer analysis time for an 8 hour recording was 15 and 13 minutes, respectively. The analysis of frequency distribution overnight showed for the material as a whole 63% of no activity, 33% of 0-2 contractions x min-1 and 4% of more than 2 contractions x min-1. Modality analysis showed a peak between 15 and 25 seconds. Approximately 30% of the tracings showed accumulated intervals, which were multiples of the peak. No significant correlation was found between the first and second night of observation regarding the number of contractions and maximum frequency overnight. Significant correlation was found for the number of periods with high frequency activity between the two nights (p less than 0.05). Long-term pressure activity can be analyzed using the presented computer-aided method, providing a rapid and objective measurement of classical parameters and access to more in-depth analysis. This actual study of normal overnight rectal activity showed a large inter- and intra-individual variation.