Abstract
In 1978, Dravet proposed a clinical entity called severe myoclonic epilepsy in infancy
(SMEI). In the same year, a patient group, which was later called high voltage slow
wave-grand mal syndrome (HVSW-GM), is reported in Japan. Both syndromes are very similar,
except for seizure manifestation: generalized tonic–clonic convulsions (GTC) with
myoclonic and other polymorphic seizures in SMEI vs. GTC only in HVSW-GM. To study
the pathophysiology of these refractory epilepsies, the author formulated new clinical
diagnostic criteria common to both syndromes as follows: GTC with onset before the
age of 1 year as the principal seizure type; an epilepsy entity unclassifiable either
as partial or generalized by all the clinical data including EEG findings; mental
and motor dysfunction absent prior to seizure onset but appearing later; absence of
epileptiform activities on EEG in the initial stage; stubborn refractoriness to conventional
antiepileptic medication. Twenty-two patients meeting all of five clinical criteria
above mentioned were recruited in the study. Detailed analysis of clinico-electrical
features and long-term follow-up of these patients led the author to the conclusion
that GTC in combination with seizures of other types will contribute to an unfavorable
pathophysiological or prognostic conditions, and, especially when GTC exists in combination
with myoclonic seizures, the severity of epilepsy will increase. The author claimed
that the three clinical entities, SMEI, HVSW-GM, and their variant form, share certain
characteristics in common and may constitute a unique epilepsy syndrome for which
a new name of infantile refractory grand mal syndrome (IRGMS) was offered. This is
a more basic concept with broader spectrum than SMEI, encompassing not only SMEI but
also related borderlands like HVSW-GM. More recently, the author observed that early
zonisamide medication within 1 year after seizure onset may improve seizure prognosis
in IRGMS, by preventing the development of myoclonic seizures.
Keywords
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Article info
Publication history
Accepted:
July 20,
2001
Received in revised form:
July 17,
2001
Received:
March 21,
2001
Identification
Copyright
© 2001 Elsevier Science B.V. Published by Elsevier Inc. All rights reserved.
