title: Analysis of ciliary beat pattern and beat frequency using digital high speed imaging: comparison with the photomultiplier and photodiode methods.
abstract: BACKGROUND
  The aim of this study was to determine the relationship of the power and recovery stroke of respiratory cilia using digital high speed video imaging. Beat frequency measurements made using digital high speed video were also compared with those obtained using the photomultiplier and modified photodiode techniques.
  
  
  METHODS
  Ciliated epithelium was obtained by brushing the inferior nasal turbinate of 20 healthy subjects. Ciliated edges were observed by microscopy and the deviation of cilia during their recovery stroke relative to the path travelled during their power stroke was measured. Beat frequency measurements made by digital high speed video analysis were compared with those obtained using the photomultiplier and modified photodiode.
  
  
  RESULTS
  Cilia were found to beat with a forward power stroke and a backward recovery stroke within the same plane. The mean angular deviation of the cilia during the recovery stroke from the plane of the forward power stroke was only 3.6 degrees (95% CI 3.1 to 4.1). There was a significant difference in beat frequency measurement between the digital high speed video (13.2 Hz (95% CI 11.8 to 14.6)) and both photomultiplier (12.0 Hz (95% CI 10.8 to 13.1), p = 0.01) and photodiode (11.2 Hz (95% CI 9.9 to 12.5), p<0.001) techniques. The Bland-Altman limits of agreement for the digital high speed video were -2.75 to 5.15 Hz with the photomultiplier and -2.30 to 6.06 Hz with the photodiode.
  
  
  CONCLUSIONS
  Respiratory cilia beat forwards and backwards within the same plane without a classical sideways recovery sweep. Digital high speed video imaging allows both ciliary beat frequency and beat pattern to be evaluated.
authors.affiliation: Department of Child Health, University of Leicester School of Medicine, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, P O Box 65, Leicester LE2 7LX, UK.
authors.forename: M A
authors.initials: MA
authors.lastname: Chilvers
authors.forename: C
authors.initials: C
authors.lastname: O'Callaghan
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002923:Cilia / Q000502:physiology*; D003952:Diagnostic Imaging; D005260:Female; D006801:Humans; D008297:Male; D014420:Turbinates / Q000166:cytology*; D014741:Video Recording / Q000379:methods*