Electrophysiological characteristics of seizure clusters.
The phenomenon of temporal clustering of seizures is well known, but its effect on seizure localization has not been rigorously analyzed. The aim of our study was to assess electrophysiological localization during Video EEG (VEEG) monitoring in patients with intractable epilepsy demonstrating a cluster of seizures. The study was conducted on 203 intractable epilepsy patients, aged 2 to 60 years (19.96 +/- 10.87). Patients with unilateral temporal lobe epilepsy having clusters were compared with patients not having clusters, and the effect of clustering on concordance was addressed. Fully consistent localization was observed in 116 patients, partially consistent localization in 18 patients, and inconsistent localization in 19 patients. ANOVA did not reveal any significant difference in these groups (p=0.65). A total of 770 seizures recorded from 149 patients was analyzed for clustering effect. Clustering was present in 603/770 seizures pairs (78.31%). In the cluster group, 483 (80.09%) seizure pairs were concordant for seizure onset, while 98 (16.25%) were discordant and 22 (3.65%) were indeterminate. In the noncluster group, 134 (80.24%) seizure pairs were concordant for seizure onset, while 23 (13.77%) were discordant and 10 (5.98%) were indeterminate. The study found that cluster seizures occurring within an interseizure interval (ISI) less than 8 hours are independent and have the same localizing value as those seizures with longer ISIs.
Tripathi
M
M
Department of Neurology, All India Institute of Medical Sciences, New Delhi, India. manjari.tripathi@gmail.com
Singh
P K
PK
Vibha
D
D
Choudhary
N
N
Garg
A
A
Bal
C S
CS
Sarkar
C
C
Bhatia
R
R
Padma
M V
MV
Gaikwad
S
S
Singh
M B
MB
Prasad
K
K
Chandra
P S
PS
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D004569:Electroencephalography / Q000379:methods*; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D014741:Video Recording