Myoclonic seizures combined with partial seizures and probable pathophysiology of secondary bilateral synchrony.
OBJECTIVE
We report on a patient who showed an unusual transition from complex partial seizures to a combination of myoclonic seizures and partial seizures, and then to isolated myoclonic seizures. The pathophysiological mechanism of the myoclonic seizures in this uncommon condition was studied.


METHODS
The interhemispheric small time differences were estimated in the ictal EEG discharges of myoclonic seizures for differentiation between primary and secondary bilateral synchrony. The estimation was performed by coherence and phase analysis based on the two-dimensional autoregressive model.


RESULTS
The estimated interhemispheric time differences were at most 27.4 ms. The ictal activity of the myoclonic seizures was suggested to originate from a cortical focus in the right hemisphere, which was also the origin of the partial seizures.


CONCLUSIONS
The patient was considered to have an unusual type of myoclonic seizures with a probable pathophysiological mechanism of secondary bilateral synchrony.
Kobayashi
K
K
Department of Child Neurology, Okayama University Medical School, 700-8558, Okayama, Japan. k_koba@med.okayama-u.ac.jp
Maniwa
S
S
Ogino
T
T
Yoshinaga
H
H
Ohtsuka
Y
Y
Oka
E
E
D001921:Brain / Q000503:physiopathology*; D002648:Child; D004569:Electroencephalography; D004831:Epilepsies, Myoclonic / Q000503:physiopathology*; D004828:Epilepsies, Partial / Q000503:physiopathology*; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male