High‐frequency oscillations as a new biomarker in epilepsy
Top Cited Papers
- 2 August 2011
- journal article
- review article
- Published by Wiley in Annals of Neurology
- Vol. 71 (2), 169-178
- https://doi.org/10.1002/ana.22548
Abstract
The discovery that electroencephalography (EEG) contains useful information at frequencies above the traditional 80Hz limit has had a profound impact on our understanding of brain function. In epilepsy, high‐frequency oscillations (HFOs, >80Hz) have proven particularly important and useful. This literature review describes the morphology, clinical meaning, and pathophysiology of epileptic HFOs. To record HFOs, the intracranial EEG needs to be sampled at least at 2,000Hz. The oscillatory events can be visualized by applying a high‐pass filter and increasing the time and amplitude scales, or EEG time‐frequency maps can show the amount of high‐frequency activity. HFOs appear excellent markers for the epileptogenic zone. In patients with focal epilepsy who can benefit from surgery, invasive EEG is often required to identify the epileptic cortex, but current information is sometimes inadequate. Removal of brain tissue generating HFOs has been related to better postsurgical outcome than removing the seizure onset zone, indicating that HFOs may mark cortex that needs to be removed to achieve seizure control. The pathophysiology of epileptic HFOs is challenging, probably involving populations of neurons firing asynchronously. They differ from physiological HFOs in not being paced by rhythmic inhibitory activity and in their possible origin from population spikes. Their link to the epileptogenic zone argues that their study will teach us much about the pathophysiology of epileptogenesis and ictogenesis. HFOs show promise for improving surgical outcome and accelerating intracranial EEG investigations. Their potential needs to be assessed by future research. Ann Neurol 2012;71:169–178This publication has 80 references indexed in Scilit:
- Statistical mapping of ictal high-frequency oscillations in epileptic spasmsEpilepsia, 2010
- Removing interictal fast ripples on electrocorticography linked with seizure freedom in childrenNeurology, 2010
- Unsupervised Classification of High-Frequency Oscillations in Human Neocortical Epilepsy and Control PatientsJournal of Neurophysiology, 2010
- Spontaneous and evoked high‐frequency oscillations in the tetanus toxin model of epilepsyEpilepsia, 2010
- Epileptic high-frequency network activity in a model of non-lesional temporal lobe epilepsyBrain, 2010
- Spatial characterization of interictal high frequency oscillations in epileptic neocortexBrain, 2009
- Three‐dimensional surface maps link local atrophy and fast ripples in human epileptic hippocampusAnnals of Neurology, 2009
- High-frequency oscillations in human temporal lobe: simultaneous microwire and clinical macroelectrode recordingsBrain, 2008
- Fast oscillations associated with interictal spikes localize the epileptogenic zone in patients with partial epilepsyNeuroImage, 2008
- Human and automated detection of high-frequency oscillations in clinical intracranial EEG recordingsClinical Neurophysiology, 2007