title: [Misleading aspects of the standard electroencephalogram in juvenile myoclonic epilepsy: a retrospective study of 56 consecutive cases].
abstract: Atypical clinical and/or EEG presentation may complicate the diagnosis of juvenile myoclonic epilepsy (JME). To assess the sensitivity of a standard EEG recording, we retrospectively evaluated the EEG performed at their first referral in 56 consecutive JME patients first seen between 1986 and 1992 (26 M, 30 F, aged 12-53, mean 24.4, with onset of JME at age 10-33, mean 14.3). The diagnosis had been made in none of these patients prior to referral, and was often confirmed only during follow-up. A 20-minute standard EEG was recorded, including hyperventilation (HV) and intermittent light stimulation (ILS). This EEG was normal in 15 cases (27%), showing aspecific or misleading changes in 11 cases (20%) and typical changes in only 30 cases (54%). The baseline EEG was normal in 25 (45%), atypical in 11 (20%), and typical for JME in only 20 (35%). HV and ILS yielded 37 and 39 normal, 10 and 7 aspecific and 9 and 10 specific findings, respectively. A single standard EEG without activation may thus be inconclusive or misleading for the diagnosis of JME in more than 50% of newly referred patients.
authors.affiliation: Centre Saint-Paul, Marseille, France.
authors.forename: P
authors.initials: P
authors.lastname: Genton
authors.forename: M S
authors.initials: MS
authors.lastname: Gonzalez Sanchez
authors.forename: A
authors.initials: A
authors.lastname: Saltarelli
authors.forename: M
authors.initials: M
authors.lastname: Bureau
authors.forename: C
authors.initials: C
authors.lastname: Dravet
authors.forename: J
authors.initials: J
authors.lastname: Roger
mesh_terms: D000293:Adolescent; D000328:Adult; D001810:Blood Volume / Q000502:physiology; D002648:Child; D003951:Diagnostic Errors; D004569:Electroencephalography; D004831:Epilepsies, Myoclonic / Q000175:diagnosis / Q000503:physiopathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006985:Hyperventilation / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
vernacular_title: Electroencéphalogramme standard et ses aspects trompeurs dans l'épilepsie myoclonique juvénile: étude rétrospective de 56 cas consécutifs.