A Systematic Review of the Influence of Bolus Characteristics on Respiratory Measures in Healthy Swallowing

Pilot Study of Respiratory-Swallow Coordination in Amyotrophic Lateral Sclerosis

PURPOSE

Amyotrophic lateral sclerosis (ALS) impacts bulbar and respiratory musculature, which may contribute to impaired swallow function (dysphagia) and respiratory-swallow coordination. The purpose of this pilot study was to examine if respiratory-swallow coordination in individuals with ALS was perturbed compared to healthy controls. We further explored relationships between measures of respiratory function and self-reported swallowing outcomes on respiratory-swallow coordination.

METHOD

We employed a cross-sectional design with eight participants with ALS and eight age- and sex-matched healthy participants. Respiratory inductance plethysmography and a nasal cannula were used to capture respiratory-swallow phase patterns during a standardized clinical swallow examination. The advantageous respiratory-swallow phase pattern was defined if exhalation surrounded the swallow (E-E). Spirometry was used to capture indices of respiratory function (forced vital capacity % predicted, peak cough flow [PCF]). Validated questionnaires were used to collect information regarding ALS-related bulbar functional status and swallowing-related concerns.

RESULTS

Compared to the matched healthy cohort, individuals with ALS demonstrated higher rates of non-E-E respiratory-swallow phase patterning and worse bulbar/swallow dysfunction. Group (ALS), swallow tasks, and PCF were significantly associated with respiratory-swallow phase pattern.

CONCLUSIONS

These preliminary findings support altered respiratory-swallow phase patterning in ALS. Future work should employ an instrumental assessment to quantify swallowing physiology and elucidate the relationship between perturbed respiratory-swallow coordination and swallowing function.

Effects of Bolus Holding on Respiratory-Swallow Coordination in Parkinson's Disease

PURPOSE

The aim of this study was to examine the effects of bolus holding on respiratory-swallow coordination (RSC) in people with Parkinson's disease (PD).

METHOD

People with PD were prospectively recruited to undergo RSC assessment using simultaneous respiratory inductive plethysmography and flexible laryngoscopy. During RSC assessment, participants swallowed 5-ml thin liquid boluses during held and nonheld swallowing tasks. Measures of RSC were analyzed for each swallow, which included respiratory pause duration, lung volume at swallow initiation, respiratory phase patterning, and the presence of paradoxical respiratory movements. Multilevel statistical modeling was used to determine if differences in RSC were present between the held and nonheld tasks.

RESULTS

Thirty-three participants were enrolled. When compared to the nonheld swallows, the held swallows exhibited shorter respiratory pauses (p = .001, R ² = .019), lower lung volumes at swallow initiation (p < .001, R ² = .116), more frequent exhale-swallow-exhale patterns (p < .001, OR = 4.30), and less frequent paradoxical respiratory movements (p = .001, OR = 0.43).

CONCLUSIONS

Findings from this study revealed that bolus holding significantly influences RSC in people with PD. This demonstrates that bolus holding may be an efficacious strategy to immediately improve RSC in PD. However, clinicians and researchers should consider avoiding bolus holding during swallowing evaluations if attempting to assess RSC behaviors that are most typical for the examinee.