新生児呼吸音の音響学的解析

概要

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To assess the auscultative changes of breath sounds in various age groups, we compared the characteristics of breath sounds in normal newborn infants to older children by means of frequency spectral analysis.<BR>Our subjectswerefull-term infants within 7 days of age (n=55), and children age 10 months to 14 years (n=21). Breath sounds were recorded simultaneously via a microphone attached to the chest and impedance pneumography. Sound signals were band-passed from 100 to 1000Hz and analyzed using the fast Fourier transform (FFT). Peak frequency (PF) of the spectra of breath sounds was significantly higher in newborns than in older children (p<0.001), and the decline of the power spectra (SLOPE) from PF was not significantly different between three groups. However, SLOPE demonstrated linear correlation with PF both in newborns and in older children respectively. This study suggests that the difference of lung sounds between newborn infants and older children is considered to be originated from their sound source rather than from their transmission effect.