STEREO-EEG EXPLORATION OF PERIVENTRICULAR NODULAR HETEROTOPIA AND OVERLYING CORTEX IN PATIENTS WITH INTRACTABLE FOCAL EPILEPSY
Abstract number :
1.306
Submission category :
Year :
2002
Submission ID :
887
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Yahya Agha Khani, Frederick Andermann, Li Min Li, Lahbib Soualmi, Andre Olivier, Francois Dubeau. Department of Neurology and Neurosurgery, Montreal Neurological Hospital and Institute, Montreal, Quebec, Canada; Department of Neurology, University of Camp
RATIONALE: We studied patients with periventricular nodular heterotopia (PNH) and medically intractable focal epilepsy to define the role of the heterotopic grey matter nodules and the cortex on epileptogenesis.
METHODS: All patients (n=8) with PNH and intractable focal epilepsy who underwent Stereo-EEG evaluation at the Montreal Neurological Hospital and Institute between February 1994 and April 2002 were reviewed. Patients were implanted stereotactically using an image guidance system (SSN inc. Montreal, Canada). We included only those in which at least one nodule was explored. The epileptic focus was defined according to the result of the intracranial ictal recordings.
RESULTS: Six patients(3 men, mean age at seizure onset, 11.6 years) were studied. Periventricular nodular heterotopia were bilateral, diffuse and contiguous in two, bilateral focal in two and unilateral focal in two. All but one had bilateral electrode implantation and the number of nodules explored varied from one to five per patient. Two hundred and ten electrographic and electro-clinical seizures were reviewed. In two patients(one with bilateral contiguous PNH, one with a single nodule in the right atrium), seizure onset was in an atrophic hippocampus and no interictal or ictal epileptic activity (EA) was seen in the heterotopia studied. In another patient (with two adjacent nodules in the left occipital horn), seizure onset was in the adjacent occipital neocortex within two cm of the nodules. In the three remaining patients (one with bilateral contiguous PNH, and two with bilateral focal PNH), seizure onset was regional, multifocal or bilateral in the overlying temporo-occipital cortices (two patients) or fronto-temporal (in a patient who had an additional frontal lesion). Occasional additional interictal and ictal EA was also seen in one or several grey matter nodules.
CONCLUSIONS: Patients with PNH often have intractable epilepsy. Seizures may result from complex interaction between the heterotopia and cortex, may be due to dual pathology and occasionnaly the nodule may be contralateral to the focus. Invasive recordings are essential to understand the role of PNH in epileptogenesis.