Cepstral Acoustics of Pre- and Post-Swallow Voice in Persons with Neurogenic Dysphagia

The laryngeal function can be significantly affected by the neurological insults, in turn disturbing both voice and swallowing functions. Several researchers have explored voice evaluation in persons with dysphagia. But a significant research gap in the inclusion of acoustic and cepstral measures still exists. The current study aimed to identify the post-swallow voice changes (DSV) in individuals diagnosed with neurogenic dysphagia. A cross-sectional comparative study was conducted with 63 adults diagnosed with oropharyngeal dysphagia and 65 phono-normals without swallowing difficulties. All participants produced a sustained /a/ sound before and after a series of standardized swallow trials. Pre- and post-swallow voice samples were analyzed using acoustic and cepstral measures, and a difference score (DSV) was calculated for each parameter. People with dysphagia showed much larger pre-post changes than typical adults in fundamental frequency measures, jitter, shimmer, other perturbation measures, and noise-related indices. They also showed greater changes in cepstral measures such as cepstral peak prominence, low-to-high spectral ratio, and cepstral spectral index of dysphonia. These results indicate that, after swallowing, voice becomes less stable and less periodic in individuals with dysphagia, probably due to residue near the vocal folds and reduced airway protection. Overall, the findings suggest that analyzing the voice changes before and after swallowing can provide an objective, non-invasive, and swift yet quantitative measure to flag possible dysphagia. Cepstral measures in particular appear to be promising markers that could complement clinical and instrumental swallowing assessments in screening and monitoring people at risk.