An Acoustic Profile of Normal Swallowing

Cervical auscultation has been proposed as a technique to augment the clinical evaluation of dysphagia to improve its accuracy in the diagnosis of dysphagia. Before using cervical auscultation to reliably diagnose disordered swallowing, it is necessary to first acoustically characterize normal swallowing for comparison with dysphagic swallowing. Ninety-seven healthy adult participants consumed teaspoon boluses of various consistencies while the sounds of swallowing were recorded. Descriptive statistics were reported for measures of duration, intensity, and frequency of the acoustic swallowing signal. Correlations between the variables and between bolus consistencies were computed. Overall, results compared favorably with previous research. Significant correlations were found among several of the variables, including an increasing duration of the acoustic swallowing signal with increasing age and decreasing intensity of the signal with increasing age. None of the variables differed significantly as a function of gender. Of potential clinical relevance, significant correlations between bolus consistencies for the duration and intensity variables indicated relative similarities across bolus consistencies. Duration and intensity of the acoustic signal appeared to be the most reliable of the variables measured. These results could serve as a reference point for future studies into normal swallowing across multiple bolus consistencies and volumes and eventually be compared with disordered swallowing.