01-High frequency oscillations – A revolution in electroencephalography?

Abstract

From its very birth in 1924, the clinical electroencephalography (EEG) underwent a relatively smooth evolution, in which the most important milestones have been digitalization and introduction of advanced methods for mathematical analyses of EEG signals. In the clinical practice however, we still evaluate the same curves as Hans Berger did almost one century ago, and their visual analysis remains a gold standard for all the time of EEG method’s utilization. Nevertheless, in the last decade we faced a convincing proofs of existence and practical contribution of the piece of information hidden in the EEG curve, about which we had no idea till the of the 20th century. Electrophysiological events with frequencies above 100 Hz can be detected in EEG signals recorded using high sampling frequency. Namely high frequency oscillations (HFOs) that have been repeatedly observed in invasive micro- and macro-EEG, are nowadays considered as a very promising electrophysiological biomarker of the epileptogenic zone. For tomorrow extremely challenging can be scalp recordings of HFOs, which is currently heavily studied and possibly might dramatically change the face of clinical electroencephalography in years ahead.