title: Inferring seizure frequency from brief EEG recordings.
abstract: Routine EEGs remain a cornerstone test in caring for people with epilepsy. Although rare, a self-limited seizure (clinical or electrographic only) may be observed during such brief EEGs. The implications of observing a seizure in this situation, especially with respect to inferring the underlying seizure frequency, are unclear. The issue is complicated by the inaccuracy of patient-reported estimations of seizure frequency. The treating clinician is often left to wonder whether the single seizure indicates very frequent seizures, or if it is of lesser significance. We applied standard concepts of probabilistic inference to a simple model of seizure incidence to provide some guidance for clinicians facing this situation. Our analysis establishes upper and lower bounds on the seizure rate implied by observing a single seizure during routine EEG. Not surprisingly, with additional information regarding the expected seizure rate, these bounds can be further constrained. This framework should aid the clinician in applying a more principled approach toward decision making in the setting of a single seizure on a routine EEG.
authors.affiliation: MGH Epilepsy Service, Massachusetts General Hospital, and Harvard Medical School, Boston, MA, USA. mwestover@partners.org
authors.forename: M Brandon
authors.initials: MB
authors.lastname: Westover
authors.forename: Matt T
authors.initials: MT
authors.lastname: Bianchi
authors.forename: Mouhsin
authors.initials: M
authors.lastname: Shafi
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Hoch
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cole
authors.forename: Keith
authors.initials: K
authors.lastname: Chiappa
authors.forename: Sydney S
authors.initials: SS
authors.lastname: Cash
mesh_terms: D004569:Electroencephalography / Q000379:methods*; D006801:Humans; D008962:Models, Theoretical; D012640:Seizures / Q000175:diagnosis* / Q000503:physiopathology
references.citation: Int J Epidemiol. 2009 Apr;38(2):337-41
references.pmid: 19179346
references.citation: Neurology. 1996 Jul;47(1):260-4
references.pmid: 8710091
references.citation: Arch Neurol. 2007 Nov;64(11):1595-9
references.pmid: 17998441
references.citation: Epilepsy Curr. 2008 Jul-Aug;8(4):92-3
references.pmid: 18596872
references.citation: Epilepsy Behav. 2006 Sep;9(2):281-5
references.pmid: 16824803