High-frequency oscillations of ictal muscle activity and epileptogenic discharges on intracranial EEG in a temporal lobe epilepsy patient

Hiroshi Otsubo, Ayako Ochi, Katsumi Imai, Tomoyuki Akiyama, Ayataka Fujimoto, Cristina Go, Peter Dirks, Elizabeth J. Donner

Research output: Contribution to journalArticlepeer-review

68 Citations (Scopus)


Objective: During seizures, intracranial EEG electrodes can record ictal muscle movements. Our purpose was to differentiate the high-frequency oscillations (HFOs) of extracranial muscle contractions from those of intracranial epileptogenic discharges. Methods: Using intracranial video-EEG (IVEEG), we recorded seizures in a 17-year-old boy with left mesial-temporal lobe epilepsy. We used multiple band frequency analysis (MBFA) to differentiate extracranial HFOs of craniofacial muscle activities from intracranial HFOs recorded ictally and interictally. Results: During 11 seizures, IVEEG showed low-amplitude fast waves (∼60 Hz) starting at the left mesial-temporal electrodes. Ictal facial grimacing projected low-amplitude (∼20 μV) fast waves (∼160 Hz) on inferior lateral-temporal electrodes. Interictal chewing projected medium-amplitude (∼100 μV) fast waves (∼140 Hz) correlating to mouth movements. MBFA topographic power spectrograms revealed a sustained, consistent ictal fast-frequency band from electrodes in the seizure-onset zone and randomly scattered HFOs without a specific frequency band from ictal and interictal extracranial muscle contractions. Conclusions: MBFA power spectrograms differentiated randomly scattered muscle HFOs without a specific frequency band at electrodes close to temporal muscles from ictal epileptic HFOs with a sustained, fast-frequency band in the seizure-onset zone. Significance: The pattern and distribution of frequency power spectrograms of extracranial HFOs differ from those of intracranial HFOs.

Original languageEnglish
Pages (from-to)862-868
Number of pages7
JournalClinical Neurophysiology
Issue number4
Publication statusPublished - Apr 2008
Externally publishedYes


  • High-frequency oscillations
  • Intracranial video-EEG
  • Multiple band frequency analysis
  • Muscle high-frequency oscillations
  • Temporal lobe epilepsy

ASJC Scopus subject areas

  • Sensory Systems
  • Neurology
  • Clinical Neurology
  • Physiology (medical)


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