ICTAL EEG PATTERNS OF GENERALIZED ONSET SEIZURES WITH PARTIAL ICTAL PROGRESSIONS
Abstract number :
1.105
Submission category :
Year :
2002
Submission ID :
1602
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Steve S. Chung, Jong M. Rho. Neurology, UC Irvine Medical Center, Orange, CA; Pediatrics, UC Irvine Medical Center, Orange, CA
RATIONALE: Secondarily generalized seizures are marked electrographically by spreading ictal patterns throughout the two cerebral hemispheres, unlike generalized-onset seizures where such progression is believed not to occur. We describe two unusual cases of partial progression of generalized-onset seizures, mistakenly diagnosed as partial-onset seizures prior to long-term video-EEG monitoring (LTM).
METHODS: Five seizures were recorded from two young patients (age 9 and 20 years) during inpatient LTM. Both patients had been previously diagnosed with partial-onset epilepsy based solely on observation by family members. Monopolar recordings were obtained using the standard 10-20 electrode system supplemented with sphenoidal electrodes. Ictal recordings were reviewed utilizing sequential bipolar and referential montages.
RESULTS: Three seizures were recorded in the younger patient, each starting with sudden behavioral arrest and then lip-smacking. With seizure #2, she had right-sided posturing with forceful head deviation to the same side. With seizure #3, she had head and eye deviation to the left with a right hand automatism. Ictal EEG revealed initial generalized 3 Hz spike-wave discharges for 2-3 seconds, followed by diffuse delta slowing for 5-6 seconds. The slow rhythm then progressed to lateralized spike-wave discharges (over the left temporal lobe with seizure #2, but over the right temporal lobe with seizure #3), which then generalized after 10 seconds. In the older patient, two seizures were recorded, each beginning with behavioral arrest and staring lasting 4-5 seconds. Seizure semiology did not reveal any lateralizing features. Ictal EEG was remarkable for an initial 1-second period of generalized low-voltage fast activity (GPFA), followed by left temporal spike-wave discharges lasting 3 seconds.
CONCLUSIONS: Progression of generalized onset seizures can at times resemble partial onset seizures. Laterality of ictal semiology may sometimes lead to the misdiagnosis of partial-onset seizures, resulting in inappropriate medical treatment, lest LTM is employed.