title: Spontaneous swallowing frequency has potential to identify dysphagia in acute stroke.
abstract: OBJECTIVE
  Spontaneous swallowing frequency has been described as an index of dysphagia in various health conditions. This study evaluated the potential of spontaneous swallow frequency analysis as a screening protocol for dysphagia in acute stroke.
  
  
  METHODS
  In a cohort of 63 acute stroke cases, swallow frequency rates (swallows per minute [SPM]) were compared with stroke and swallow severity indices, age, time from stroke to assessment, and consciousness level. Mean differences in SPM were compared between patients with versus without clinically significant dysphagia. Receiver operating characteristic curve analysis was used to identify the optimal threshold in SPM, which was compared with a validated clinical dysphagia examination for identification of dysphagia cases. Time series analysis was used to identify the minimally adequate time period to complete spontaneous swallow frequency analysis.
  
  
  RESULTS
  SPM correlated significantly with stroke and swallow severity indices but not with age, time from stroke onset, or consciousness level. Patients with dysphagia demonstrated significantly lower SPM rates. SPM differed by dysphagia severity. Receiver operating characteristic curve analysis yielded a threshold of SPM≤0.40 that identified dysphagia (per the criterion referent) with 0.96 sensitivity, 0.68 specificity, and 0.96 negative predictive value. Time series analysis indicated that a 5- to 10-minute sampling window was sufficient to calculate spontaneous swallow frequency to identify dysphagia cases in acute stroke.
  
  
  CONCLUSIONS
  Spontaneous swallowing frequency presents high potential to screen for dysphagia in acute stroke without the need for trained, available personnel.
authors.affiliation: From the Swallowing Research Laboratory (M.A.C., G.D.C., I.S.), Departments of Speech, Language, and Hearing Science (M.A.C.), Behavioral Science and Community Health (G.D.C.), and Neurology (A.K., M.W.), University of Florida Health Science Center, Gainesville.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Crary
authors.forename: Giselle D
authors.initials: GD
authors.lastname: Carnaby
authors.forename: Isaac
authors.initials: I
authors.lastname: Sia
authors.forename: Anna
authors.initials: A
authors.lastname: Khanna
authors.forename: Michael F
authors.initials: MF
authors.lastname: Waters
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003679:Deglutition / Q000502:physiology*; D003680:Deglutition Disorders / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D020521:Stroke / Q000150:complications* / Q000503:physiopathology; D013997:Time Factors
keywords: deglutition disorders; diagnosis; stroke