title: Predicting the activation states of the muscles governing upper esophageal sphincter relaxation and opening.
abstract: The swallowing muscles that influence upper esophageal sphincter (UES) opening are centrally controlled and modulated by sensory information. Activation and deactivation of neural inputs to these muscles, including the intrinsic cricopharyngeus (CP) and extrinsic submental (SM) muscles, results in their mechanical activation or deactivation, which changes the diameter of the lumen, alters the intraluminal pressure, and ultimately reduces or promotes flow of content. By measuring the changes in diameter, using intraluminal impedance, and the concurrent changes in intraluminal pressure, it is possible to determine when the muscles are passively or actively relaxing or contracting. From these "mechanical states" of the muscle, the neural inputs driving the specific motor behaviors of the UES can be inferred. In this study we compared predictions of UES mechanical states directly with the activity measured by electromyography (EMG). In eight subjects, pharyngeal pressure and impedance were recorded in parallel with CP- and SM-EMG activity. UES pressure and impedance swallow profiles correlated with the CP-EMG and SM-EMG recordings, respectively. Eight UES muscle states were determined by using the gradient of pressure and impedance with respect to time. Guided by the level and gradient change of EMG activity, mechanical states successfully predicted the activity of the CP muscle and SM muscle independently. Mechanical state predictions revealed patterns consistent with the known neural inputs activating the different muscles during swallowing. Derivation of "activation state" maps may allow better physiological and pathophysiological interpretations of UES function.
authors.affiliation: Department of Human Physiology, School of Medicine, Flinders University, Adelaide, Australia; and Department of Gastroenterology & Surgery, Flinders Medical Centre, Adelaide, Australia; and taher.omari@flinders.edu.au.
authors.forename: Taher I
authors.initials: TI
authors.lastname: Omari
authors.affiliation: Department of Surgery, Division of Otolaryngology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Corinne A
authors.initials: CA
authors.lastname: Jones
authors.affiliation: Department of Surgery, Division of Otolaryngology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hammer
authors.affiliation: Department of Gastroenterology & Surgery, Flinders Medical Centre, Adelaide, Australia; and.
authors.forename: Charles
authors.initials: C
authors.lastname: Cock
authors.affiliation: Department of Human Physiology, School of Medicine, Flinders University, Adelaide, Australia; and Department of Gastroenterology & Surgery, Flinders Medical Centre, Adelaide, Australia; and.
authors.forename: Philip
authors.initials: P
authors.lastname: Dinning
authors.affiliation: Department of Human Physiology, School of Medicine, Flinders University, Adelaide, Australia; and.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Wiklendt
authors.affiliation: Department of Human Physiology, School of Medicine, Flinders University, Adelaide, Australia; and.
authors.forename: Marcello
authors.initials: M
authors.lastname: Costa
authors.affiliation: Department of Surgery, Division of Otolaryngology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: McCulloch
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena; D003679:Deglutition / Q000502:physiology; D004576:Electromyography; D049631:Esophageal Sphincter, Upper / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008365:Manometry; D009119:Muscle Contraction / Q000502:physiology; D009126:Muscle Relaxation; D009130:Muscle, Smooth / Q000502:physiology*; D010614:Pharynx / Q000502:physiology; D011312:Pressure; D055815:Young Adult
keywords: cricopharyngeus muscle; deglutition; diameter; dysphagia; electromyography; impedance; neural pathways; pressure; submental muscles; upper esophageal sphincter