Circadian and ultradian patterns of epileptiform discharges differ by seizure-onset location during long-term ambulatory intracranial monitoring

David Spencer, Felice T. Sun, Sarah N. Brown, Barbara C. Jobst, Nathan B. Fountain, Victoria Wong, Emily A. Mirro, Mark Quigg

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

Objective: Previous studies reporting circadian patterns of epileptiform activity and seizures are limited by (1) short-term recording in an epilepsy monitoring unit (EMU) with altered antiepileptic drugs (AEDs) and sleep, or (2) subjective seizure diary reports. We studied circadian patterns using long-term ambulatory intracranial recordings captured by the NeuroPace RNS System. Methods: Retrospective study of RNS System trial participants with stable detection parameters over a continuous 84-day period. We analyzed all detections and long device–detected epileptiform events (long episodes) and defined a subset of subjects in whom long episodes represented electrographic seizures (LE-SZ). Spectrum resampling determined the dominant frequency periodicity and cosinor analysis identified significant circadian peaks in detected activity. Chi-square analysis was used to compare subjects grouped by region of seizure onset. Results: In the 134 subjects, detections showed a strongly circadian and uniform pattern irrespective of region of onset that peaked during normal sleep hours. In contrast, long episodes and LE-SZ patterns varied by region. Neocortical regions had a monophasic, nocturnally dominant rhythm, whereas limbic regions showed a more complex pattern and diurnal peak. Rhythms in some individual limbic subjects were best fit by a dual oscillator (circadian + ultradian) model. Significance: Epileptiform activity has a strong 24 h periodicity with peak nocturnal occurrence. Limbic and neocortical epilepsy show divergent circadian influences. These findings confirm that circadian patterns of epileptiform activity vary by seizure-onset zone, with implications for treatment and safety, including SUDEP.

Original languageEnglish (US)
Pages (from-to)1495-1502
Number of pages8
JournalEpilepsia
Volume57
Issue number9
DOIs
StatePublished - Sep 1 2016

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Ambulatory Monitoring
Seizures
Periodicity
Epilepsy
Sleep
Anticonvulsants
Retrospective Studies
Safety

Keywords

  • Circadian rhythms
  • Epilepsy
  • Epileptiform
  • Responsive neurostimulation

ASJC Scopus subject areas

  • Medicine(all)
  • Neurology
  • Clinical Neurology

Cite this

Circadian and ultradian patterns of epileptiform discharges differ by seizure-onset location during long-term ambulatory intracranial monitoring. / Spencer, David; Sun, Felice T.; Brown, Sarah N.; Jobst, Barbara C.; Fountain, Nathan B.; Wong, Victoria; Mirro, Emily A.; Quigg, Mark.

In: Epilepsia, Vol. 57, No. 9, 01.09.2016, p. 1495-1502.

Research output: Contribution to journalArticle

Spencer, David ; Sun, Felice T. ; Brown, Sarah N. ; Jobst, Barbara C. ; Fountain, Nathan B. ; Wong, Victoria ; Mirro, Emily A. ; Quigg, Mark. / Circadian and ultradian patterns of epileptiform discharges differ by seizure-onset location during long-term ambulatory intracranial monitoring. In: Epilepsia. 2016 ; Vol. 57, No. 9. pp. 1495-1502.
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