title: Swallowing activity assessed by ambulatory impedance-pH monitoring predicts awake and asleep periods at night.
abstract: BACKGROUND
  Voluntary muscle activity, including swallowing, decreases during the night. The association between nocturnal awakenings and swallowing activity is under-researched with limited information on the frequency of swallows during awake and asleep periods.
  
  
  OBJECTIVE
  The aim of this study was to assess nocturnal swallowing activity and identify a cut-off predicting awake and asleep periods.
  
  
  METHODS
  Patients undergoing impedance-pH monitoring as part of GERD work-up were asked to wear a wrist activity detecting device (Actigraph(®)) at night. Swallowing activity was quantified by analysing impedance changes in the proximal esophagus. Awake and asleep periods were determined using a validated scoring system (Sadeh algorithm). Receiver operating characteristics (ROC) analyses were performed to determine sensitivity, specificity and accuracy of swallowing frequency to identify awake and asleep periods.
  
  
  RESULTS
  Data from 76 patients (28 male, 48 female; mean age 56 ± 15 years) were included in the analysis. The ROC analysis found that 0.33 sw/min (i.e. one swallow every 3 min) had the optimal sensitivity (78 %) and specificity (76 %) to differentiate awake from asleep periods. A swallowing frequency of 0.25 sw/min (i.e. one swallow every 4 min) was 93 % sensitive and 57 % specific to identify awake periods. A swallowing frequency of 1 sw/min was 20 % sensitive but 96 % specific in identifying awake periods. Impedance-pH monitoring detects differences in swallowing activity during awake and asleep periods. Swallowing frequency noticed during ambulatory impedance-pH monitoring can predict the state of consciousness during nocturnal periods.
authors.affiliation: Division of Gastroenterology and Hepatology, Digestive Disease Center, Medical University of South Carolina, Charleston, SC, USA. daniel.pohl@usz.ch
authors.forename: D
authors.initials: D
authors.lastname: Pohl
authors.forename: F
authors.initials: F
authors.lastname: Arevalo
authors.forename: E
authors.initials: E
authors.lastname: Singh
authors.forename: J
authors.initials: J
authors.lastname: Freeman
authors.forename: R
authors.initials: R
authors.lastname: Tutuian
authors.forename: D O
authors.initials: DO
authors.lastname: Castell
mesh_terms: D056044:Actigraphy; D000328:Adult; D000368:Aged; D003243:Consciousness; D003679:Deglutition / Q000502:physiology*; D050782:Esophageal pH Monitoring; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012890:Sleep / Q000502:physiology*; D012893:Sleep Wake Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology