Pharyngeal Electrical Stimulation favorably modifies healthy human pharyngo-esophageal function - a randomized trial using High Resolution Manometry Impedance.

Background: Despite positive clinical evidence for the effects of Pharyngeal Electrical Stimulation (PES) on swallowing performance in disease, it remains unknown which specific swallow characteristics improve. Using High Resolution Manometry Impedance (HRMI) with Pressure Flow Analysis (PFA), we aimed to assess the effects of PES on normal swallow function and to evaluate the impact of pharyngeal length variability on electrode placement.

Methods: As part of a prospective RCT, 20 asymptomatic volunteers were randomly assigned to three days of PES or SHAM treatment. HRMI assessments were conducted at baseline (during which pharyngeal length measurements were acquired) and repeated at 1-2 hours, and at 24-72 hours following PES or SHAM treatment.

Key Results: Twenty healthy adults (10 male, median age: 28.0 (IQR 23.8-45.0) years, age range: 20-65 years) participated in this RCT. We developed an objective, standardized method of catheter placement based on pharyngeal length measurements. Over 3 days, the median stimulation intensity of PES was 11 mA. When compared to the SHAM group, the PES group scored better on multiple pharyngeal and esophageal metrics resulting in improved global swallow function values 1-2 hours after treatment (p=0.029). One day later, most of these beneficial effects were no longer present.

Conclusions: This study suggests that PES can temporarily alter swallow function in healthy individuals. Functional reserve in healthy individuals may be further enhanced by PES. In the majority of volunteers, electrode position needed to be adjusted 1-3 cm to account for variations in pharyngeal length.