Electrocorticography and outcome in frontal lobe epilepsy.
The prognostic significance of epileptiform activity (EA) recorded at electrocorticography (ECOG) was examined in a group of 60 consecutive non-tumoral patients with intractable frontal lobe epilepsy (FLE). Pre-excision EA was documented as absent, focal (one gyrus), regional (two gyri), lobar (3 gyri) or multilobar (frontal + temporal gyri). Post-excision EA was documented as absent, restricted to the resection border, or recorded distant to the resection border, and was quantitated by spike frequency. Pre-excision EA from < or = 2 gyri and absence of post-resection EA correlated with Class I or II (Engel classification) outcome while pre-excision EA from > or = 3 gyri and persistent post-resection EA, especially distant to the resection border, correlated with Class III or IV outcome (P < 0.001). A significant correlation between poorer outcomes and increased abundance of distant post-resection EA was observed (P < 0.001). EA restricted to the resection border was not significantly correlated with outcome. Presence of a circumscribed lesion correlated with Class I outcome (P < 0.01) and absence of pathological abnormality correlated with Class IV outcome (P < 0.05). Neither side nor extent of surgical excision correlated with outcome. EA recorded at ECOG is of prognostic significance in FLE. A lobar or multilobar distribution of pre-excision EA and persistent post-excision EA distant to the resection border, especially when abundant, are highly unfavorable prognostic indicators. In contrast, a restricted distribution of pre-excision EA and absence of post-resection EA both herald a favorable outcome.
Wennberg
R
R
Department of Neurology and Neurosurgery, Montreal Neurological Institute and Hospital, McGill University, Quebec, Canada.
Quesney
F
F
Olivier
A
A
Rasmussen
T
T
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography; D017034:Epilepsy, Frontal Lobe / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009458:Neuroleptanalgesia; D011379:Prognosis; D016896:Treatment Outcome