electroencephalography (eeg) is an electrophysiological monitoring technique to record electrical activity of the brain. it is generally noninvasive, with the electrodes placed along the scalp, even though invasive electrodes are once in a while used, as in electrocorticography. eeg measures voltage fluctuations attributable to ionic modern-day within the neurons of the brain. clinically, eeg refers to the recording of the brain's spontaneous electrical hobby over a period of time, as recorded from more than one electrodes placed at the scalp. diagnostic programs typically attention both on occasion-associated potentials or at the spectral content material of eeg. the former investigates ability fluctuations time locked to an event, together with 'stimulus onset' or 'button press'. the latter analyses the type of neural oscillations (popularly known as "mind waves") that may be determined in eeg signals within the frequency area.
eeg is most usually used to diagnose epilepsy, which reasons abnormalities in eeg readings. it's also used to diagnose sleep issues, intensity of anesthesia, coma, encephalopathies, and mind dying. eeg was a first-line method of analysis for tumors, stroke and other focal mind problems, but this use has decreased with the appearance of excessive-decision anatomical imaging strategies inclusive of magnetic resonance imaging (mri) and computed tomography (ct). no matter restrained spatial resolution, eeg is still a treasured device for studies and prognosis. it is one of the few mobile strategies to be had and gives millisecond-range temporal decision which isn't always possible with ct, puppy or mri.
derivatives of the eeg method encompass evoked potentials (ep), which entails averaging the eeg activity time-locked to the presentation of a stimulus of a few type (visible, somatosensory, or auditory). event-related potentials (erps) seek advice from averaged eeg responses which might be time-locked to greater complex processing of stimuli; this approach is utilized in cognitive science, cognitive psychology, and psychophysiological research.