motor manifestation syncope finding MC, 20110126: The Brighton guideline on which this is based needs to be checked. Email correspondance with Brighton: [MC] One thing is unclear to me: Level 1 of diagnostic certainty is defined as "witnessed sudden loss of consciousness AND generalized, tonic, clonic, tonic–clonic, or atonic motor manifestations." A footnote adds: atonic in the absence of: hypotonic hyporesponsive episode (as defined by the Brighton Collaboration), syncope, and myoclonic jerks. If we define syncope as being a loss of consciousness, how can I have a witnessed sudden loss of consciousness and a generalized atonic motor manifestation in the absence of syncope? [Brighton] Thank you for your question. You are right, that there is an overlap between the clinical presentation of an atonic seizure and a Syncope. This is also true for HHE. This is the very reasonf or the footnote to alert the user of the definition to this differential diagnosis. If you are working on a database and only have the clinical criteria vailable, you may have some false positives for the atonic seizure cases, unless you obtain additional information, e.g. that the Syncope was vasovagal or orthostatic, or arrhythmic, etc. http://en.wikipedia.org/wiki/Syncope_%28medicine%29 loss of consciousness, fainting