Insular Cortex within Paralimbic Networks: Interictal and Ictal Intracerebral EEG Patterns in Refractory Temporal Lobe Epilepsy
Abstract number :
3.183
Submission category :
Year :
2001
Submission ID :
3031
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
S. Chassagnon, MD, Neurology, Clinique Neurologique, Strasbourg, France; L. Minotti, MD, Neurophysiopathologie, Neurology, Grenoble, France; D. Hoffmann, MD, Neurochirurgie, Neurology, Grenoble, France; E. Hirsch, MD, Clinique Neurologique, Neurology, Str
RATIONALE: To study the fonction of the insular cortex in the propagation and genesis of discharges coming from limbic and paralimbic areas.
METHODS: 15 partial epileptic patients who underwent stereotaxic intracerebral EEG monitoring (SEEG) before surgery were selected for this study. All of them had had interical and ictal recordings of hippocampus, amygdala and insular, neocortical temporal, temporopolar, orbitofrontal and anterior cingulate regions. Insular cortex was investigated with an electrode inserted according to an original oblique antero-posterior and dorso-ventral trajectory.
RESULTS: No morbidity was related to the insular electrodes. Ictal involvement of the insular cortex during temporolimbic seizures occured in the majority of patients, most often simultaneously or after the temporopolar region, generally without subsequent involvement of the opercular cortex. Epileptiform events were always restricted to a part of the whole number of contact of the insular electrode. Considering all the patients, ictal symptomatology didn[ssquote]t included peculiar clinical effects whether the insular cortex was clearly and precociously affected or not during temporal lobe originating seizures. In two patients, abondant interictal independent insular spikes coincided with early propagation of seizures from mesio-temporal to insular region but waren[ssquote]t predictive of seizures originating in the insular cortex. Anterior cingulate and orbito-frontal cortex could be in addition concerned, associated in one case with a mimicry of fear and a shivering behaviour.
CONCLUSIONS: Insular exploration with an oblique antero-posterior electrode seems to be a safe procedure, allowing recordings of different insular gyri along a rostro-caudal axis. As recently highlighted by Isnard et al., the insular cortex seems to be mostly involved in the ictal electroclinic pattern of temporal lobe seizures. However and unlike the temporopolar region, the insular cortex usually doesn[ssquote]t belong to the epileptogenic zone.