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Acoustic characteristics of voluntary expiratory sounds after swallow for detecting dysphagia
Author(s) -
Yamashita M.,
Yokoyama K.,
Takei Y.,
Furuya N.,
Nakamichi Y.,
Ihara Y.,
Takahashi K.,
Groher M. E.
Publication year - 2014
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1111/joor.12184
Subject(s) - dysphagia , medicine , decibel , audiology , radiology
Summary This research was designed to investigate the acoustic characteristics of voluntary expiratory sounds after swallow for detecting dysphagia. Forty‐nine patients with complaints of swallow difficulty received a videofluorographic ( VF ) examination. They were divided into three groups: nine who did not have any apparent disease ( G roup N ), 22 patients with head and neck cancer ( G roup H&N ) and 18 patients with other diseases including cerebrovascular disease ( G roup OD ). After liquid barium swallows, they exhaled voluntarily without voicing. Videofluorographic findings were classified into four groups: normal ( N ormal), acceptable swallow (Acceptable), swallow with residue (Resid) and swallows with penetration or aspiration (Pen/Asp). The duration of expiratory sounds was measured on the time waveform. Frequency characteristics of expiratory sounds were obtained using one‐third octave band analysis ranging from 62·5 to 2000·0 Hz of central frequency. The averaged level of the 1000·0‐Hz band was chosen as the reference band level ( RB level). The revised averaged level of each band was obtained by subtracting the RB level from the averaged level of each band. Zero decibel of the revised magnitude of the 125·0‐Hz band was set as the critical value to differentiate dysphagia ( R esid or Pen/Asp) from no dysphagia ( N ormal or A cceptable). Comparison of this assessment with VF findings showed a significant percentage agreement (85·4%). These results suggest that frequency characteristics of post‐swallow expiratory sounds can differentiate dysphagia from no dysphagia among multiple dysphagic patient groups.