A Review of the Importance of Acoustic Features of Wet Voice Quality in Diagnosing Patients with Swallowing Disorders

Objective: Swallowing problems, including aspiration, lead to acoustic changes in the voice. In many cases, these changes are the first symptoms of swallowing disorders. Acoustic evaluations are non-invasive, accurate, and reliable tools that can complement other clinical evaluations like video fluoroscopy in screening patients at risk of swallowing disorders. Recognizing the voice quality resulting from swallowing disorders and studying the acoustic changes in voice by the dysphagia treatment team, especially speech and language pathologists, is essential. The aim of this study is to review articles that have investigated the voice quality resulting from swallowing disorders and acoustic changes in voice.

Methods/Design: This study is a review article and was conducted by searching available databases including PubMed, Science Direct, Google Scholar, and Scopus using keywords such as dysphagia, wet vocal quality, aspiration, and voice analysis. Articles with more relevance to the research objective were selected and their results were combined.

Results: Out of the conducted studies, 23 articles that took place from 2000 to 2021 were selected. They focused on acoustic evaluations in swallowing disorders, aspiration, and the comparison of acoustic and perceptual evaluations in aspiration. The wet voice quality, perceptually marked by the presence of fluid in the larynx during voicing, is one of the voice qualities resulting from swallowing disorders. According to the conducted studies, this voice quality presents with signs such as increased shimmer, jitter, harmonic-to-noise ratio, and changes in fundamental frequency.

Conclusion: Acoustic changes can be a reliable tool for the initial screening and diagnosis of aspiration during swallowing and have greater accuracy compared to initial perceptual evaluations by the dysphagia treatment team.