Relationship between post-stroke dysphagia and pharyngeal sensory impairment

Abstract

Background Post-stroke dysphagia (PSD) is common and can lead to serious complications. Pharyngeal sensory impairment is assumed to contribute to PSD. The aim of this study was to investigate the relationship between PSD and pharyngeal hypesthesia and to compare different assessment methods for pharyngeal sensation. Methods In this prospective observational study, fifty-seven stroke patients were examined in the acute stage of the disease using Flexible Endoscopic Evaluation of Swallowing (FEES). The Fiberoptic Endoscopic Dysphagia Severity Scale (FEDSS) and impaired secretion management according to the Murray-Secretion Scale were determined, as well as premature bolus spillage, pharyngeal residue and delayed or absent swallowing reflex. A multimodal sensory assessment was performed, including touch-technique and a previously established FEES-based swallowing provocation test with different volumes of liquid to determine the latency of swallowing response (FEES-LSR-Test). Predictors of FEDSS, Murray-Secretion Scale, premature bolus spillage, pharyngeal residue, and delayed or absent swallowing reflex were examined with ordinal logistic regression analyses. Results Sensory impairment using the touch-technique and the FEES-LSR-Test were independent predictors of higher FEDSS, Murray-Secretion Scale, and delayed or absent swallowing reflex. Decreased sensitivity according to the touch-technique correlated with the FEES-LSR-Test at 0.3 ml and 0.4 ml, but not at 0.2 ml and 0.5 ml trigger volumes. Conclusions Pharyngeal hypesthesia is a crucial factor in the development of PSD, leading to impaired secretion management and delayed or absent swallowing reflex. It can be investigated using both the touch-technique and the FEES-LSR-Test. In the latter procedure, trigger volumes of 0.4 ml are particularly suitable.

Observational study of effects of pharyngeal stimulation by carbonated solution on repetitive voluntary swallowing in humans

“…Pharyngeal hypesthesia constitutes a crucial factor in the development of dysphagia. [ 24 ] Injecting NaCl slowly into the pharyngeal region can be considered as an approach to simulate the reduced sensation in the pharynx. The very slow infusion of NaCl + CA solution minimized mechanical and water sensory information from the pharyngeal mucosa, allowing for the appearance of the sensory effect of carbonation on swallowing.…”

“…By injecting carbonated NaCl solution into the pharynx at a slow infusion rate, it is possible to study the effects of carbonic acid stimulation on swallowing without exciting the water-sensitive neurons and mechanoreceptors present in the pharynx. As pharyngeal hypesthesia plays a crucial role in the development of dysphagia, [ 24 ] investigating the physiological mechanisms underlying the facilitation of swallowing via pharyngeal sensory stimulation by carbonation may lead to the development of novel approaches to swallowing rehabilitation. Thus, we hypothesize that carbon dioxide-sensitive neurons exist in the pharyngeal region, and only the effect of bolus carbonation in facilitating swallowing can be investigated using carbonated NaCl solutions.…”

Systematic approach to contextualize findings of flexible endoscopic evaluation of swallowing in neurogenic dysphagia– towards an integrated FEES report

“…This test was validated in healthy subjects and clearly distinguished between the physiological state and experimentally induced pharyngeal anesthesia, in addition inter- and intra-rater reliability were excellent [ 63 ]. In further studies pharyngeal hypesthesia as documented by the FEES-LSR-Test was correlated with dysphagia severity both in stroke victims [ 64 ] and in community-dwelling older adults [ 65 ].…”

The impact of physical therapy on dysphagia in neurological diseases: a review

“…Dysphagia following stroke primarily stems from cerebral cortex and subcortical structures damage, affecting areas like the motor cortex, cerebellum, thalamus, and other parts, as well as sensory defects of the pharyngeal mucosa ( Teismann et al, 2007 ; Qin et al, 2023 ). It is characterized by a delayed or absent swallowing reflex and a premature overflow of bolus ( Labeit et al, 2023 ), pharyngeal food residues and pharyngeal motility disorders ( Warnecke et al, 2021 ). A dysphagia caused by Parkinson’s disease is different from dysphagia caused by stroke because it is primarily caused by problems with the brainstem, muscle atrophy, and dopaminergic and non-dopaminergic mechanisms ( Patel et al, 2020 ).…”