Unconscious confusion--a literature search for definitions of syncope and related disorders.
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.
Thijs
Roland D
RD
Dept. of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, 9600, 2300 RC Leiden, The Netherlands.
Benditt
David G
DG
Mathias
Christopher J
CJ
Schondorf
Ronald
R
Sutton
Richard
R
Wieling
Wouter
W
van Dijk
J Gert
JG
D001341:Autonomic Nervous System / Q000503:physiopathology*; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis* / Q000503:physiopathology*; D013575:Syncope / Q000175:diagnosis* / Q000503:physiopathology*