Nocturnal hypermotor seizures, suggesting frontal lobe epilepsy, can originate in the insula.
OBJECTIVE
To report three patients with drug-resistant nocturnal hypermotor seizures (NHSs), no detectable brain lesion, and clinically defined nocturnal frontal lobe epilepsy (NFLE) or autosomal dominant NLFE (ADNFLE), whose intracerebral EEG ictal onset primarily involved the insula, rather than the mesial or orbital frontal cortex.


METHODS
Fourteen to 15 intracerebral electrodes were implanted in each patient, primarily sampling the frontal lobes with 80 to 91 recording leads covering the most likely side of seizure onset, and two to six leads placed within the ipsilateral insula. Electrical stimulation was used to test the epileptic threshold of frontal and insular brain regions at the various recording sites.


RESULTS
In all three patients, a low-voltage fast activity was recorded within the anterosuperior aspect of the insula at ictal onset, either in isolation, or extending to the nearby frontal operculum in the ADNFLE patient. The role of the insula was further supported in all three patients either by the presence of high-amplitude spikes that clearly predominated over that region (n = 2) or by triggering the patient's typical aura or seizure when applying an electrical stimulation at that site, selectively (n = 2).


CONCLUSIONS
The anterosuperior portion of the insula might play a pivotal role in generating nocturnal hypermotor seizures in some patients with nonlesional drug-resistant epilepsy suggesting NFLE or ADNFLE. Whether these patients are amenable to successful surgery remain an open issue.
Ryvlin
Philippe
P
Department of Functional Neurology and Epileptology, Hospices Civils de Lyon and Université Claude Bernard Lyon 1, Lyon, France. ryvlin@cermep.fr
Minotti
Lorella
L
Demarquay
Geneviève
G
Hirsch
Edouard
E
Arzimanoglou
Alexis
A
Hoffman
Dominique
D
Guénot
Marc
M
Picard
Fabienne
F
Rheims
Sylvain
S
Kahane
Philippe
P
D000293:Adolescent; D000927:Anticonvulsants / Q000627:therapeutic use; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000503:physiopathology*; D002648:Child; D004351:Drug Resistance; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D004569:Electroencephalography / Q000706:statistics & numerical data*; D004827:Epilepsy / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D017034:Epilepsy, Frontal Lobe / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics; D020183:Nocturnal Paroxysmal Dystonia / Q000175:diagnosis / Q000503:physiopathology; D017286:Polysomnography; D011978:Receptors, Nicotinic / Q000235:genetics; D012640:Seizures / Q000175:diagnosis / Q000235:genetics / Q000503:physiopathology*
D000927:Anticonvulsants; D011978:Receptors, Nicotinic