Differences in pharyngeal swallow event timing: Healthy aging, Parkinson disease, and amyotrophic lateral sclerosis

The pharyngeal phase of swallowing involves a coordinated sequence of events. Event durations may be prolonged in people with Parkinson disease (PwPD), and amyotrophic lateral sclerosis (PwALS); however, the cumulative effect of these changes is unexplored. We compared event latencies relative to hyoid burst (HYB) (time zero) to understand differences in deglutatory event timing. We hypothesized PwPD and PwALS would display similarly prolonged cumulative pharyngeal phase durations compared to healthy controls, with greater prolongations with increasing bolus viscosity.

We retrospectively evaluated videofluoroscopic data of healthy adults (n = 78), PwPD (n = 17), and PwALS (n = 20). Participants swallowed 15 boluses of 20% (w/v) barium across five liquid consistencies. Paired raters evaluated nine deglutitive events using the ASPEKT method. Latencies were plotted by consistency relative to HYB and compared across cohorts using Mann-Whitney U tests (p ≤ .05). Cohen's d was calculated for all statistically significant results to determine effect size.

In PwPD, significantly prolonged latencies were observed on thin liquid boluses compared to healthy controls. Latencies to all post-HYB events were significantly prolonged except for maximum upper esophageal sphincter distension. In PwALS, significantly prolonged latencies for events preceding and following HYB were noted on all consistencies compared to healthy controls and PwPD.

In PwPD, event latencies for multiple components of the swallowing sequence were prolonged culminating in overall prolongation of the pharyngeal phase on thin liquid. A similar pattern, but with significantly greater prolongation, was seen in the PwALS, and extended to swallows of all liquid consistencies.