Some EEG patterns, such as regional attenuation of faster frequencies without delta (RAWOD), may reflect early severe loss of CBF (mean 8.6 ml/100 g/min) as seen during large occlusive infarcts, leading to complications such as edema and herniation [ 13].
A subsequent EEG five months later showed marked abnormality with no normal rhythmicity and intermittent projected activity consisting of high voltage delta and multifocal sharp waves in bursts with attenuation of faster frequencies.
A variety of quantitative EEG (qEEG) measures have been used clinically to quantify slowing or attenuation of faster frequencies in the EEG, specifically: The calculation of power within different frequency bands (i.e., delta, theta, alpha, and beta); ratios or percentages of power in specific frequency bands; and spectral edge frequencies (based on the frequency under which x% of the EEG resides).
Our recovery data comes from three seizures analysed from a single patient, so should be viewed only as preliminary data, but what is clear is that the recovery of these two features is far in advance of the recovery of normal function in this subject, who experienced prolonged post-ictal lethargy with typical corresponding EEG changes (slowing and loss of faster frequencies).
Regional changes, including a lack of delta or the presence of faster frequencies within 24 hours, correlate with a good outcome [ 23] while the persistence of unilateral prominent, continuous delta slowing or decreased alpha adds significantly to clinical predictions of poor outcome [ 24].
In [3], concepts of fast frequency hopping along with OFDM are illustrated.
When DR-based reserves comprise the majority of fast frequency reserves, then dynamic simulations using a power system model are required, because frequency is substantially affected by the behaviour of these sources.
During bursting induced by SK block in vitro, spiking begins at a low frequency, but just prior to entry into depolarization block, often a burst of fast frequency, full amplitude spikes is emitted; these particular spikes may provide an in vitro analog of operationally defined bursts (see Introduction) in vivo.
In this paper we investigate this hypothesis and the underlying biophysical and dynamic mechanism that leads to hyper-excitable firing in SCs, including the role played by synaptic inhibition (opposing the effects of synaptic excitation) and the mechanism of termination of fast frequency spiking leading to hyper-excitable bursts similar to the ones observed experimentally [31].
With the development of fast frequency domain OCT systems, multiple B-Scan recordings at the same or nearly the same positions became possible.
