title: Unconscious confusion--a literature search for definitions of syncope and related disorders.
abstract: BACKGROUND
  Imprecise definitions of syncope and related conditions appear common in the medical literature. To investigate the scope of the problem we systematically searched for definitions in high-ranking medical journals.
  
  
  METHODS
  Literature review of articles on 'syncope', 'neurocardiogenic syncope', 'neurally mediated syncope', 'orthostatic intolerance', and 'orthostatic hypotension' with these keywords in the title, mainly published in the ten journals with the highest impact in the fields of cardiology, internal medicine, and neurology.
  
  
  RESULTS
  Syncope, neurocardiogenic syncope, neurally mediated syncope, orthostatic intolerance, and orthostatic hypotension were defined in only 41%, 34%, 26%, 38%, and 48% of papers respectively. Definitions, when given, differed considerably among papers. Orthostatic hypotension was most frequently defined, with an increase in number and consistency of definitions after publication of a consensus in 1996.
  
  
  CONCLUSIONS
  Syncope and related conditions proved to be infrequently and inconsistently defined in current medical literature. The lack of consistent terminology is likely to harm medical education, research, and patient care. There is a strong need for a systematic terminology for syncope and related conditions.
authors.affiliation: Dept. of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, 9600, 2300 RC Leiden, The Netherlands.
authors.forename: Roland D
authors.initials: RD
authors.lastname: Thijs
authors.forename: David G
authors.initials: DG
authors.lastname: Benditt
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Mathias
authors.forename: Ronald
authors.initials: R
authors.lastname: Schondorf
authors.forename: Richard
authors.initials: R
authors.lastname: Sutton
authors.forename: Wouter
authors.initials: W
authors.lastname: Wieling
authors.forename: J Gert
authors.initials: JG
authors.lastname: van Dijk
mesh_terms: D001341:Autonomic Nervous System / Q000503:physiopathology*; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis* / Q000503:physiopathology*; D013575:Syncope / Q000175:diagnosis* / Q000503:physiopathology*