Are high frequency oscillations associated with altered network topology in partial epilepsy?
Eric van Diessen1, Judith I Hanemaaijer, Willem M Otte
1Rudolf Magnus Institute of Neuroscience, Department of Pediatric Neurology, University Medical Center Utrecht, the Netherlands. E.vanDiessen-3@umcutrecht.nl
Neuroimage
|June 25, 2013
Summary
This study found that the epileptic zone in temporal lobe epilepsy shows reduced connectivity, or
Area of Science:
- Neuroscience
- Epileptology
- EEG analysis
Background:
- Epilepsy is characterized by altered brain functional networks, particularly in the theta frequency band.
- Brain 'hubs' (highly interconnected regions) are implicated in epileptic networks.
- High frequency oscillations (HFOs) are novel biomarkers for identifying the epileptogenic zone, stemming from altered neuronal interactions.
Purpose of the Study:
- To investigate the association between the epileptogenic zone and pathological brain hubs.
- To determine if HFOs correlate with hub measures in epilepsy.
Main Methods:
- Bilateral depth electrode recordings from hippocampus and amygdala in 12 epilepsy patients.
- Marking of HFOs (ripples, fast ripples) and spikes during slow-wave sleep.
- Computation of hub measures from non-epileptiform periods in the intracranial EEG.
Main Results:
- The epileptogenic zone showed decreased theta band hub values.
- Higher amounts of HFOs, especially fast ripples, correlated negatively with channel hub values.
- Similar trends were observed in broad and gamma frequency bands.
Conclusions:
- The epileptogenic zone may exhibit pathological functional 'isolation' during the interictal state.
- HFOs, particularly fast ripples, are linked to reduced network connectivity in the epileptic focus.
- These findings contribute to understanding the network dynamics of temporal lobe epilepsy.
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