Electroencephalography (EEG)

Abstract

Electroencephalography is a domain concerning recording and interpretation of the electroencephalogram. Electroencephalogram (EEG) is a record of the electric signal generated by the cooperative action of brain cells, or more precisely, the time course of an extracellular field potentials generated by their synchronous action. Electroencephalogram derives from the Greek words enkephalo (brain) and graphein (to write). EEG can be measured by means of electrodes placed on the scalp or directly on the cortex. In the latter case, it is sometimes called electrocorticogram (ECoG). Electric fields measured intracortically were named Local Fields Potentials (LFP). EEG recorded in the absence of an external stimulus is called spontaneous EEG; EEG generated as a response to external or internal stimulus is called an event‐related potential (ERP. The amplitude of EEG of a normal subject in the awake state recorded with the scalp electrodes is 10–100 μV. In case of epilepsy, the EEG amplitudes may increase by almost an order of magnitude. In the cortex, amplitudes are in the range 500–1500 μV.

Drowsiness detection for single channel EEG by DWT best m-term approximation

“…According to Blinowska and Durka (2006), the basic criterion for accepting an automatic method in the EEG analysis is its agreement to visual inspection of the hypnogram. According to the same authors, the correlation between the same classifications made by different specialists is 87.5% which is not high enough for implementing a safety system.…”

“…The sleep process starts with the activation and inhibition of neurons in different brain areas. As this process is rhythmic and synchronized, when observed through EEG signals it is identified by: (i) decreased activity of beta rhythm ([13-30]Hz); (ii) increase and subsequent reduction of alpha rhythm activity ([8-13]Hz); and (iii) increased theta rhythm activity ([4-8]Hz) (Blinowska and Durka, 2006).…”

Optimal determination of wavelet for football player EEG using SVM classifier

“…All these mentioned waves speak to various mental conditions of an individual [9,10]. EEG signals consist of little amplitudes and can be effortlessly defiled by artifacts.…”

“…The real time recording of the EEG signal from the subject's scalp is demonstrated as in Figure 3. EEG action at the accompanying electrodes locales: (AF3, F7, F3, FC5, T7, P7, O1, O2, P8, T8, FC6, F4, F8 and AF4) were recorded [5,10], as represented in Figure 4. Electrodes are appended to the skin using conductive glue with impedances, for the most part, kept underneath 5 kΩ.…”

Detecção de sonolência através de aproximação não-linear associada ás transformadas wavelet e de Fourier

“…Por ser rítmico e sincronizado, pode ser analisado através da variação da amplitude da corrente elétrica no cérebro, detectável através da eletroencefalografia (EEG). A sonolênciá e então caracterizada por (i) decréscimo de atividade no ritmo beta ([13-30]Hz); (ii) aumento e subsequente redução de atividade no ritmo alfa ( [8][9][10][11][12][13]Hz) e (iii) aumento de atividade no ritmo teta ( [4][5][6][7][8]Hz) [3].…”