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Updated: May 18, 2026

Adapting Human Videofluoroscopic Swallow Study Methods to Detect and Characterize Dysphagia in Murine Disease Models
Published on: March 1, 2015
Fast Fourier transform analysis of sounds made while swallowing various foods
Mitsuru Taniwaki1, Kaoru Kohyama
1National Food Research Institute, National Agriculture and Food Research Organization, 2-1-12, Kannondai, Tsukuba, Ibaraki 305-8642, Japan.
Abstract:
The cervical auscultation method was applied to investigate sounds generated while swallowing various foods with unique physical properties, including liquid (water), semiliquid (yogurt), and solid (konjac jelly). To study the differences among swallowing sounds for various foods, fast Fourier transform (FFT) analysis was applied to signals that were attributed to the flow of a food bolus, which is a swallowable soft mass of chewed food. An FFT program was developed that enabled the calculation of a spectrum for a specified region of time domain swallowing sound signals. The intensity of spectra in the frequency range between 400 and 1000 Hz significantly differed: liquid > semiliquid > solid. The FFT spectrum in this range was suggested to represent the frequency characteristics of the swallowing sounds of various foods.
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