FEES‐based assessment of pharyngeal hypesthesia—Proposal and validation of a new test procedure

Abstract

Background Intact pharyngeal sensation is essential for a physiological swallowing process, and conversely, pharyngeal hypesthesia can cause dysphagia. This study introduces and validates a diagnostic test to quantify pharyngeal hypesthesia. Methods A total of 20 healthy volunteers were included in a prospective study. Flexible endoscopic evaluation of swallowing (FEES) and a sensory test were performed both before and after pharyngeal local anesthesia. To test pharyngeal sensation, a small tube was positioned transnasally in the upper third of the oropharynx with contact to the lateral pharyngeal wall. Increasing volumes of blue‐dyed water were injected through the tube, and the latency of swallowing response (LSR) was determined by two independent raters from the endoscopic video recording. Three trials were performed for each administered volume starting with 0.1 mL and increased by 0.1 mL up to 0.5 mL. Key Results The average LSR without anesthesia was 2.24 ± 0.80 s at 0.1 mL, 1.79 ± 0.84 s at 0.2 mL, 1.29 ± 0.62 s at 0.3 mL, 1.17 ± 0.41 s at 0.4 mL, and 1.19 ± 0.52 s at 0.5 mL. With anesthesia applied, the average LSR was 2.65 ± 0.62 s at 0.1 mL, 2.64 ± 0.49 s at 0.2 mL, 2.44 ± 0.65 s at 0.3 mL, 2.10 ± 0.80 s at 0.4 mL, and 2.18 ± 0.85 s at 0.5 mL. LSR was significantly longer following anesthesia at 0.2 mL (t = −3.82; P = .001), 0.3 mL (t = −4.65; P < .000), 0.4 mL (t = −5.77; P < .000), and 0.5 mL (t = −3.49; P = .005). Conclusion and Inferences Pharyngeal hypesthesia can be quantified with sensory testing using LSR. Suitable volumes to distinguish between normal and impaired pharyngeal sensation are 0.2 mL, 0.3 mL, 0.4 mL and 0.5 mL. Experimentally induced pharyngeal anesthesia represents a valid model of sensory dysphagia.

Effects of cognitive and motor dual-tasks on oropharyngeal swallowing assessed with FEES in healthy individuals

“…Possibly, this domain of swallowing function is indeed controlled more reflexively and rather relies on involuntary aspects e.g. intact protective reflexes 60 and the integration of pharyngeal sensation 61 .…”

Targeting the sensory feedback within the swallowing network—Reversing artificially induced pharyngolaryngeal hypesthesia by central and peripheral stimulation strategies

“…However, because neurophysiological and functional imaging studies are difficult to conduct in these severely ill neurological patients, the underlying physiological principles involved in the restoration of sensory feedback and related central sensory processing in particular in PES are still only poorly understood. Therefore, in the present study, we made use of a previously developed “virtual lesion model” inducing transient pharyngeal and laryngeal hypesthesia in healthy adults and leading to both impaired swallowing performance and altered central sensorimotor processing (Labeit et al, 2019; Muhle, Claus, et al, 2018; Teismann et al, 2007). To revert the detrimental effects of peripheral hypesthesia on the central processing of sensory input and the swallowing motor program, we adopted PES as a peripheral stimulation tool and compared its effects to that of transcranial direct current stimulation (tDCS) applying magnetoencephalography (MEG).…”

Effect of Intestinal Levodopa-Carbidopa Infusion on Pharyngeal Dysphagia: Results from a Retrospective Pilot Study in Patients with Parkinson’s Disease

“…erefore, also nondopaminergic mechanisms are likely to be involved in the pathophysiology of PDrPD. ese include peripheral sensory impairment [36,37], decreased substance P concentration [38], and consecutively reduced cough and protective reflexes [39], as well as cortical mechanisms [40]. e individual impact of these different influencing factors has hardly been investigated.…”