PMID- 9579896
OWN - NLM
STAT- MEDLINE
DCOM- 19980521
LR  - 20190813
IS  - 0013-9580 (Print)
IS  - 0013-9580 (Linking)
VI  - 38
IP  - 8
DP  - 1997 Aug
TI  - Seizure lateralization during EEG monitoring in patients with bilateral foci: the 
      cluster effect.
PG  - 937-40
AB  - PURPOSE: To determine whether seizures that occur in clusters are more likely to 
      reflect activity of the same focus than are seizures that are widely separated in 
      time. METHODS: EEG monitoring data from 14 patients with bilateral independent 
      seizure onsets were analyzed. Twelve of the 14 patients had surface recordings 
      only, and two had implanted electrodes. Interseizure intervals (ISIs) for 151 
      seizure pairs were measured. Seizure onsets were classified as right hemispheric, 
      left hemispheric, or indeterminate. Seizure pairs were classified as concordant 
      for hemisphere of onset, discordant, or indeterminate. The relation between 
      seizure-pair concordance and ISI was examined by using univariate analysis and 
      analysis of variance (ANOVA). RESULTS: Both seizures originated from the same 
      hemisphere in 61 (75%) of 81 seizure pairs with ISIs <8 h, compared with 28 (55%) 
      of 51 seizure pairs with ISIs >8 h (p < 0.015). The cluster effect was not more 
      pronounced for ISIs <2 h. ANOVA demonstrated that the relation between ISI and 
      seizure concordance was not a result of the variability in seizure rates among 
      patients. In three patients, the presence of bilateral foci was not demonstrated 
      until more than five seizures were recorded. CONCLUSIONS: Seizures that occur 
      after an ISI of <8 h are more likely to come from the same side as the previous 
      seizure than are those with longer ISIs. Thus clustered seizures should not be 
      given the same weight as seizures widely separated in time. In addition, more 
      than five seizures may sometimes be needed to adequately assess patients being 
      evaluated for epilepsy surgery.
FAU - Haut, S R
AU  - Haut SR
AD  - Comprehensive Epilepsy Management Center, and Department of Neurology, Montefiore 
      Medical Center, Albert Einstein College of Medicine, Bronx, New York 10467-2490, 
      USA.
FAU - Legatt, A D
AU  - Legatt AD
FAU - O'Dell, C
AU  - O'Dell C
FAU - Moshe, S L
AU  - Moshe SL
FAU - Shinnar, S
AU  - Shinnar S
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Epilepsia
JT  - Epilepsia
JID - 2983306R
SB  - IM
MH  - Analysis of Variance
MH  - Cerebral Cortex/*physiopathology
MH  - Cluster Analysis
MH  - Electrodes, Implanted
MH  - Electroencephalography/methods/*statistics & numerical data
MH  - Epilepsy, Complex Partial/diagnosis/physiopathology
MH  - Functional Laterality/*physiology
MH  - Humans
MH  - Monitoring, Physiologic
MH  - Seizures/*diagnosis/physiopathology
EDAT- 1997/08/01 00:00
MHDA- 1998/05/14 00:01
CRDT- 1997/08/01 00:00
PHST- 1997/08/01 00:00 [pubmed]
PHST- 1998/05/14 00:01 [medline]
PHST- 1997/08/01 00:00 [entrez]
AID - 10.1111/j.1528-1157.1997.tb01260.x [doi]
PST - ppublish
SO  - Epilepsia. 1997 Aug;38(8):937-40. doi: 10.1111/j.1528-1157.1997.tb01260.x.