title: Modulation of Upper Esophageal Sphincter (UES) Relaxation and Opening During Volume Swallowing.
abstract: UES opening occurs following cricopharyngeus deactivation and submental muscle contraction causing hyolaryngeal elevation and UES distraction. During impedance manometry, the inverse of impedance (admittance) can be used to measure bolus presence and infer UES opening. We hypothesized that the temporal relationship between UES relaxation, opening and hyolaryngeal elevation would change with increasing bolus volume. Simultaneous intramuscular cricopharyngeal (CP) electromyography (EMG), surface submental EMG (SM-EMG), and high-resolution impedance manometry were recorded in eight (aged 27 ± 7 years, 5 M) healthy volunteers, while swallowing 0.9 % saline boluses of 2, 5, 10, and 20 ml. Data were exported and analyzed via Matlab. Statistical analysis comprised repeated measures one-way ANOVA and Pearson correlation. A P value of <0.05 was considered significant. Duration of CP deactivation increased at 20 ml volume (P < 0.001). UES relaxation and opening increased with increasing bolus volume (P < 0.001); however, overall duration of SM activation did not change. As UES opening occurs progressively earlier with increasing volumes, peak SM-EMG activity occurs relatively later (P < 0.001) and shifts from occurring before to following peak UES distention. During healthy swallowing, there is sensory modulation of cricopharyngeal and submental muscle activity. Intrabolus pressures, transmitted from the tongue base and pharynx, play a progressively more important role in sphincter opening with increasing volume. The findings may explain why some healthy elderly and patients with oropharyngeal dysphagia have difficulty swallowing larger while tolerating smaller bolus volumes.
authors.affiliation: Department of Gastroenterology & Surgery, Flinders Medical Centre & School of Medicine, Flinders University, Flinders Drive, Bedford Park, Adelaide, SA, 5042, Australia. charles.cock@flinders.edu.au.
authors.forename: Charles
authors.identifier: 0000-0003-3578-1137
authors.initials: C
authors.lastname: Cock
authors.affiliation: Division of Otolaryngology, Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Corinne A
authors.initials: CA
authors.lastname: Jones
authors.affiliation: Division of Otolaryngology, Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hammer
authors.affiliation: Department of Gastroenterology & Surgery, Flinders Medical Centre & School of Medicine, Flinders University, Flinders Drive, Bedford Park, Adelaide, SA, 5042, Australia.|Department of Human Physiology, School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: Taher I
authors.initials: TI
authors.lastname: Omari
authors.affiliation: Division of Otolaryngology, Department of Surgery, University of Wisconsin-Madison, Madison, WI, USA.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: McCulloch
mesh_terms: D000328:Adult; D003679:Deglutition / Q000502:physiology*; D004576:Electromyography; D049631:Esophageal Sphincter, Upper / Q000502:physiology*; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008365:Manometry; D009126:Muscle Relaxation; D010609:Pharyngeal Muscles / Q000502:physiology*; D011312:Pressure; D055815:Young Adult
keywords: Bolus volume; Cricopharyngeal electromyography; Deglutition; Deglutition disorders; Submental electromyography; UES opening