Acoustics Features of Cervical Auscultation in Dysphagic and Dysphonic Individuals: A Preliminary Investigation

Background: The acoustics of cervical auscultation of swallowing, a potential objective tool for the swallowing assessment, has been previously explored in clinically normal subjects. However, literature profiling the same in individuals with swallowing problems is minimal. This study estimated the acoustic features of swallowing sounds in individuals with swallowing and voice problems and compared them with the previous findings.

Method: Eight individuals diagnosed with dysphonia and dysphagia were recruited, and their cervical auscultation recordings, done using a vibration pickup conduction microphone attached to the cricoid region, were analyzed. Acoustic analysis of these cervical auscultation recordings was carried out using PRAAT software, and LTAS was extracted using Analysis of Dysphonia in Speech and Voice (ADSV).

Results: The participants showed a different acoustic pattern of swallowing sounds, including multiple waves, which were absent in the waveforms of clinically normal individuals reported in earlier studies. The mean intensity was higher in the current study participants compared to the values of clinically normal subjects reported in previous literature. This finding suggests increased strain and effort in individuals with dysphagia. The duration parameters were comparatively longer than those reported in previous literature, showing a prolonged pharyngeal stage in individuals with dysphonia and dysphagia. The peak intensity was higher. The frequency of the peak intensity values estimated using LTAS were different from the values obtained using the spectrogram.

Conclusion: The morphology of the acoustic signals of swallowing differs from the normal signals. The intensity and latency parameters also showed deviation from the normal values. The LTAS was found to be a helpful way of estimating the frequency of the peak intensity. The study was a preliminary attempt to explore the acoustic features in individuals with swallowing problems. Establishing clinical norms for parameters will help clinicians quantify the status of the swallowing problems using cervical auscultation, a non-invasive and simple assessment procedure.