Revisiting the role of the insula in refractory partial epilepsy.
OBJECTIVE
Recent evidence suggesting that some epilepsy surgery failures could be related to unrecognized insular epilepsy have led us to lower our threshold to sample the insula with intracerebral electrodes. In this study, we report our experience resulting from this change in strategy.


METHODS
During the period extending from October 2004 to June 2007, 18 patients had an intracranial study including 10 with insular coverage. The decision to sample the insula with intracerebral electrodes was made in the context of (1) nonlesional parietal lobe-like epilepsy; (2) nonlesional frontal lobe-like epilepsy; (3) nonlesional temporal lobe-like epilepsy; and (4) atypical temporal lobe-like epilepsy.


RESULTS
Intracerebral recordings confirmed the presence of insular lobe seizures in four patients. Cortical stimulation performed in 9 of 10 patients with insular electrodes elicited, in decreasing order of frequency, somatosensory, viscerosensory, motor, auditory, vestibular, and speech symptoms.


CONCLUSIONS
Our results suggest that insular cortex epilepsy may mimic temporal, frontal, and parietal lobe epilepsies and that a nonnegligeable proportion of surgical candidates with drug-resistant epilepsy have an epileptogenic zone that involves the insula.
Nguyen
Dang Khoa
DK
Service de Neurologie, Université de Montréal, Montréal, Québec, Canada.
Nguyen
Dong Bach
DB
Malak
Ramez
R
Leroux
Jean-Maxime
JM
Carmant
Lionel
L
Saint-Hilaire
Jean-Marc
JM
Giard
Normand
N
Cossette
Patrick
P
Bouthillier
Alain
A
D000328:Adult; D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000187:drug effects / Q000503:physiopathology* / Q000601:surgery; D015331:Cohort Studies; D003952:Diagnostic Imaging; D004351:Drug Resistance; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000187:drug effects*; D004828:Epilepsies, Partial / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D055815:Young Adult
D000927:Anticonvulsants