Extratemporal ictal clinical features in hippocampal sclerosis: their relationship to the degree of hippocampal volume loss and to the outcome of temporal lobectomy.
OBJECTIVE
Since extratemporal clinical features in patients with unilateral hippocampal sclerosis (HS) are likely to indicate aberrant ictal spread or a more extensive epileptogenic zone, we asked whether such features are associated with more severe HS and a worse outcome following temporal lobectomy.


METHODS
We reviewed all patients (174) who had undergone temporal lobectomy for histologically proven unilateral HS related temporal lobe epilepsy between 1997-2005 at the National Hospital for Neurology and Neurosurgery. We divided patients into those with severe HS (side-to-side ratio < 0.6) and those with mild HS (side-to-side ratio > 0.75). We examined all seizures recorded on electroencephalography (EEG) video telemetry in these patients for clinical features of temporal lobe epilepsy. The postsurgical outcome was classified using the Engel classification at the time of follow up (median 4.7 years, range 1-9 years).


RESULTS
Patients (28 out 39) with severe HS had atypical features compared to 7 out of 27 in the mild HS [Chi square (chi(2)) test, p = 0.0013]. The mean number of atypical clinical features was 2.2 in the severe HS group and 0.62 in the mild HS group (Mann Whitney U Test, p < 0.001). The percentage of postsurgery seizure freedom (class 1 Engel classification) was 87%, and there was no significant effect of the presence of atypical clinical features.


CONCLUSIONS
This study shows that atypical (extratemporal) clinical features tend to occur more frequently in patients with severe HS and do not correlate with worse surgical outcome.
Borelli
Paolo
P
Neurology Department, Università degli studi di Verona, Verona, Italy. paolo.borelli@univr.it
Shorvon
Simon D
SD
Stevens
John M
JM
Smith
Shelagh J
SJ
Scott
Catherine A
CA
Walker
Matthew C
MC
D000293:Adolescent; D000328:Adult; D038481:Anterior Temporal Lobectomy / Q000379:methods*; D004569:Electroencephalography; D004833:Epilepsy, Temporal Lobe / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery*; D005260:Female; D006624:Hippocampus / Q000033:anatomy & histology* / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012598:Sclerosis / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D012720:Severity of Illness Index