Heterogeneity of Propagation Patterns in Temporal Lobe Epilepsy Recorded with Bilateral Multilobar Subdural Electrodes
Abstract number :
1.141
Submission category :
Year :
2001
Submission ID :
2809
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
L.A. Schuh, MD, Neurology, Henry Ford Hospital, Detroit, MI; B.J. Smith, MD, Neurology, Henry Ford Hospital, Detroit, MI; K. Elisevich, MD, PhD, Neurosurgery, Henry Ford Hospital, Detroit, MI; I. Drury, MB BCh, Neurology, Henry Ford Hospital, Detroit, MI
RATIONALE: Studies of mesial temporal onset seizures (Sz) recorded from intracranial depth electrodes have revealed a limited number of ictal propagation patterns. These studies are somewhat limited by sampling. We investigated ictal propagation of mesial temporal onset Sz in those with bilateral intracranial multilobar subdural electrodes who have remained free of any postoperative Sz.
METHODS: The pictorial representations of electrode placement in all patients undergoing intracranial monitoring for treatment of medically intractable Sz were reviewed. Those with bilateral coverage of parahippocampal gyrus, lateral and basal temporal neocortex, orbitofrontal and dorsolateral frontal neocortex at a minimum were selected. Those with MRI apparent lesions were excluded. Only those who ultimately underwent anterior temporal lobectomy (ATL) and were rendered Sz free for a minimum of 1 year were selected. Their ictal recordings were reviewed in detail for propagation patterns. Subclinical and simple partial Sz were not analyzed.
RESULTS: From 1993-2000, nine patients were monitored with bilateral multilobar subdural electrodes and subsequently underwent ATL. Of those 6 were eliminated from this study due to the presence of an MRI lesion (2) or any seizure after ATL (4). Follow up ranged 37-53 months. In the 3 patients studied, an average[plusminus]SD of 124[plusminus]32 electrodes were placed and 12.7[plusminus]3.8 Sz reviewed. From ictal onset through the first 2 steps of propagation, an average of 7.7 [plusminus]3.2 patterns were seen per patient. 28% showed initial propagation to ipsilateral orbitofrontal or temporal neocortex. 20% showed inital propagation to both regions synchronously. 24% showed other patterns of initial propagation. The initial propagation time averaged 12[plusminus]9.5 seconds.
CONCLUSIONS: Greater subdural electrode coverage of patients with mesial temporal onset Sz and successful ATL demonstrate a greater variety of ictal propagation patterns than has previously been reported.