Validation of the optimal site in the neck region for detecting swallowing sounds.
Recently, the swallowing sound has been used to detect swallowing events non-invasively. A previous study, using an accelerometer, showed that the site over the lateral border of the trachea immediately inferior to the cricoid cartilage was the optimal site for detecting swallowing sounds. However, the optimal site for detection of the swallowing sound using a microphone remains undetermined. To validate the optimal site in the neck region for detecting swallowing sounds. Fourteen healthy subjects (mean age, 27·6 ± 2·2 years; seven male and seven female) participated in this study. Twenty condenser microphones were attached to 20 sites on the left neck surface to detect swallowing sounds. Participants were instructed to swallow five different stimuli three times as follows: Resting saliva, 1 and 5 mL of Japanese tea, and 1 and 5 mL of yoghurt. Mean relative peak intensity was used to indicate the magnitude of the swallowing sound. Sound spectrograms were used to illustrate differences in the properties of swallowing sounds. Mean relative peak intensity number was highest in sites at the inferior border of the mandible just above the sternocleidomastoid muscle (site 11) and sites over the lateral border of the trachea immediately inferior to the cricoid cartilage (site 8). Comparison of spectrograms showed a greater density distribution of higher frequency components at site 11 compared with site 8. These results indicate that the inferior border of the mandible just above the sternocleidomastoid muscle is the optimal site for the detection of swallowing sounds.
Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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Pan
Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan. naoto-m-10@t.okadai.jp.
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Maeda
Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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Manda
Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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Kodama
Department of Occlusal and Oral Functional Rehabilitation, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
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Minagi
D000162:Acoustics / Q000295:instrumentation; D000328:Adult; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000000981:diagnostic imaging*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009334:Neck Muscles / Q000000981:diagnostic imaging / Q000502:physiology*; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D013018:Sound Spectrography; D014132:Trachea / Q000000981:diagnostic imaging / Q000502:physiology*
acoustics; deglutition; neck; non-invasive; sound; swallowing