title: Continuous wavelet analysis of postprandial EGGs suggests sustained gastric slow waves may be slow to develop in infants with colic.
abstract: BACKGROUND
  Electrogastrography in conjunction with Fast Fourier transform has limited success in detecting low grade abnormalities in gastric electrophysiological activity owing to the non-stationarity of the signal. Analysis by continuous wavelet transform is suitable for non-stationary signals and was used to analyse EGG activity in babies with and without colic.
  
  
  METHODS
  Thirty minute postprandial EGG recordings were obtained from 23 sleeping breast-fed infants with clinically validated recurrent colic and 26 breast-fed non-colicky infants. Continuous wavelet transform analysis (CWT) identified three principal frequency components. The mean, standard deviation, and the number of frequency maxima that fell below one standard deviation from the mean were determined for each infant and each frequency.
  
  
  RESULTS
  Three component frequencies in the ranges 1.4-2.5 cpm, 2.5-4.0 cpm, and 4.0-15 cpm were found in all EGGs. Pairwise comparisons of the characteristics of each of the frequency ranges by univariate analyses showed significant differences between colicky and non-colicky subjects only in the number of maxima in the mid range of frequencies that lay below one standard deviation from the mean. However, CWT based on all frequencies allowed discrimination of the EGGS of colicky from non-colicky babies on a basis of number of frequency maxima below one standard deviation from the mean in the midrange of frequencies and in the mean and standard deviation in the low range of frequencies that was likely a harmonic of the midrange.
  
  
  CONCLUSIONS
  CWT allowed distinction of EGG signals from colicky and healthy babies. The results indicate that colic may result from tardiness in the establishment of coherent propagation of the gastric slow wave in colicky babies.
authors.affiliation: School of Food, Nutrition and Human Health, College of Health, Massey University, Palmerston North, New Zealand.
authors.forename: G W
authors.initials: GW
authors.lastname: Reynolds
authors.affiliation: School of Food, Nutrition and Human Health, College of Health, Massey University, Palmerston North, New Zealand.
authors.forename: R G
authors.initials: RG
authors.lastname: Lentle
authors.affiliation: School of Food, Nutrition and Human Health, College of Health, Massey University, Palmerston North, New Zealand.
authors.forename: P W M
authors.initials: PW
authors.lastname: Janssen
authors.affiliation: School of Food, Nutrition and Human Health, College of Health, Massey University, Palmerston North, New Zealand.
authors.forename: C M
authors.initials: CM
authors.lastname: Hulls
mesh_terms: D003085:Colic / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D019518:Postprandial Period / Q000502:physiology*; D013270:Stomach / Q000294:innervation / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D058067:Wavelet Analysis
keywords: continuous wavelet analysis; electrogastrography; infant colic