Characteristics of the swallowing sounds recorded in the ear, nose and on trachea.

Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, MB, Canada.
Medical & Biological Engineering (Impact Factor: 1.5). 07/2012; 50(8):885-90. DOI: 10.1007/s11517-012-0938-0
Source: PubMed

ABSTRACT The various malfunctions and difficulties of the swallowing mechanism necessitate various diagnostic techniques to address those problems. Swallowing sounds recorded from the trachea have been suggested as a noninvasive method of swallowing assessment. However, acquiring signals from the trachea can be difficult for those with loose skin. The objective of this pilot study was to explore the viability of using the ear and nose as alternative recording locations for recording swallowing sounds. We recorded the swallowing and breathing sounds of five healthy young individuals from the ear, nose and trachea, simultaneously. We computed time-frequency features and compared them for the different locations of recording. The features included the peak and the maximum frequencies of the power spectrum density, average power at different frequency bands and the wavelet coefficients. The average power calculated over the 4 octave bands between 150 and 2,400 Hz showed a consistent trend with less than 20 dB difference for the breath sounds of all the recording locations. Thus, analyzing breath sounds recorded from the ear and nose for the purpose of aspiration detection would give similar results to those from tracheal recordings; thus, ear and nose recording may be a viable alternative when tracheal recording is not possible.

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    ABSTRACT: We measured flow velocity of swallowed liquid passing through pharynx. We put a pressure sensor on a palate to measure tongue pressure when swallowing the liquid. And we put two acoustic sensors on the neck skin in order to measure swallowing sound when liquid passes through the pharynx. From the output of these three sensors, we can know the timing of the liquid passing through each sensor points and can calculate the flow velocity of the swallowed liquid at the pharynx. In this paper, we compare the flow velocity between two swallowing positions, “look forward position” and “look upward position.” As a result, we found that the flow velocity of the “look upward position” was 2.5 times faster than that of “look forward position.”.
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