PATTERNS OF INTRACRANIAL SEIZURE PROPAGATION
Abstract number :
2.273
Submission category :
Year :
2002
Submission ID :
3467
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Sigmund Jenssen, Colin Roberts, Dennis J. Dlugos, Michael J. O[ssquote]Connor, Michael R. Sperling. Neurology, Thomas Jefferson University, Philadelphia, PA; Pediatric Epilepsy Program, Oregon Health and Science University, Portland, OR; Neurology, Childr
RATIONALE: Little is known about pattern of seizure propagation. We studied routes and patterns of spread of complex partial and secondary generalized tonic-clonic seizures on intracranial EEG to identify ictal features.
METHODS: We divided the seizures into seven categories according to the zone of onset: three frontal zones (medial, lateral and orbital) two temporal zones (mesial and lateral) and the parietal and occipital lobes. We recorded latency of seizure spread to another lobe in the same hemisphere [ndash] ipsilateral propagation time (IPT), and latency of spread to opposite hemisphere [ndash] contralateral propagation time (CPT). All patients had EEG recorded with depth and/or subdural electrodes depending on clinical needs.
RESULTS: There were a total of 115 seizures in 40 patients. The number of seizures from the seven zones were ten, thirteen, eight, thirty, twenty-one, fifteen and eighteen, respectively.
Mean IPT by zone: mesial frontal 1.6 seconds (range 0.2[ndash]8 seconds), lateral frontal 8.15 seconds (range 6-22 seconds), orbitofrontal 47.4 seconds (range 0.4-15 seconds), mesial temporal 14.6 (range 1-47 seconds), lateral temporal 17.9 (range 0.2-57 seconds), parietal 7.8 (0.4-15 seconds), occipital 18.2 (range 0-42 seconds).
Mean CPT by zone: mesial frontal 0.35 seconds (range 0.2-1 seconds), lateral frontal 13.7 seconds (range 0.4-35 seconds), orbitofrontal 41.5 seconds (range 9.8-92 seconds), mesial temporal 34 seconds (range 1-195 seconds), parietal 23.3 seconds (range 2-54 seconds), occipital 35.4 seconds (range 27-41 seconds).
Preferred route of spread of two thirds of the seizures in each category: mesial frontal to contralateral mesial frontal, lateral frontal to ipsilateral temporal lobe, orbitofrontal to contralateral frontal lobe, mesial temporal to ipsilateral lateral temporal, lateral temporal to ipsilateral mesial temporal, parietal to frontal lobe and occipital to temporal lobe.
CONCLUSIONS: The site at which seizures originate determine propagation latency and routes of spread. This is determined by anatomic connections. Knowledge of spread pattern can help in interpreting seizure localization.