EEG and polygraphical study of vibratory generalized tonic-clonic seizures (vibratory GTCS)

M. Ogihara, A. Hoshika, T. Matsuno, T. Miyajima, K. Kinoue, C. Y. Wang, N. Yamada, Y. Oana

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


Vibratory phenomena of GTCS were analyzed by simultaneous video-EEG-polygraphic recordings in patients with severe myoclonic epilepsy (SME) and high-voltage grand mal epilepsy (HVS-grand mal). According to Gastaut, grand mal in adults consists of a tonic phase of 10-20 seconds, intermediate vibratory phase of several seconds, and clonic phase lasting for about 30 seconds. Our results demonstrated that; (1) the duration of the intermediate vibratory phase ranged 15-20 seconds, and it is significantly longer than that of adult grand mal, (2) the vibratory movements appeared when the frequency of muscular contractions decreased to 4-6 Hz, (3) the asynchronous muscular contractions of the extremities give the appearance of more rapid and tremorous movements than are actually happening, (4) the asynchrony is also observed in the clonic phase. It is speculated that such a very atypical GTCS can be ascribed to immaturity or disturbance of synchronization mechanism between the two hemispheres, which may be caused by incomplete myelination, immature synaptic structures, or disturbance of cellular interaction in patients with SME and HVS-grand mal.

Original languageEnglish
Pages (from-to)264-271
Number of pages8
JournalJournal of the Japan Epilepsy Society
Issue number3
Publication statusPublished - 1994
Externally publishedYes


  • generalized tonic-clonic seizures
  • high voltage slow wave grand mal
  • severe myoclonic epilepsy (Dravet)
  • vibratory tonic-clonic seizures

ASJC Scopus subject areas

  • Clinical Neurology
  • Neurology


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