Propagation of tonic posturing in supplementary motor area (SMA) seizures

Shinji Ohara, Akio Ikeda, Takeharu Kunieda, Shogo Yazawa, Junnya Taki, Takashi Nagamine, Waro Taki, Susumu Miyamoto, Nobuo Hashimoto, Hiroshi Shibasaki

Research output: Contribution to journalArticlepeer-review


We analyzed ictal motor symptoms in 10 patients diagnosed to have supplementary motor area (SMA) seizures based on ictal encephalographic (EEG) findings and ictal clinical semiology. Inclusion criteria were (1) EEG seizure pattern in the vertex for the scalp recording or in the area over and/or adjacent to SMA for epicortical recording and (2) ictal motor semiology characterized, as previously reported, by sudden and a brief tonic posturing of extremities and trunk mainly occurring during sleep without loss of consciousness. In 50% (5/10) of the patients, tonic posturing began in one part of the body and moved to other part(s) in 5-10 s. Unlike Jacksonian march seen in seizures involving the primary sensorimotor area (S1-M1), it spread in no accordance with the somatotopy in S1-M1. The sequential propagation of tonic posturing may represent the somatotopic organization within the SMA proper.

Original languageEnglish (US)
Pages (from-to)179-187
Number of pages9
JournalEpilepsy Research
Issue number2-3
StatePublished - Dec 2004
Externally publishedYes


  • Electrophysiology
  • Propagation pattern
  • Supplementary motor area (SMA) seizure
  • Tonic posturing

ASJC Scopus subject areas

  • Clinical Neurology
  • Pediatrics, Perinatology, and Child Health
  • Neurology


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