XLIII. Electroencephalography
XLIV. Evoked potentials
Dep. of Physiology, Fac. of Medicine, MU, 2016 © Kateřina Fialová
Electroencephalography (EEG)
• method used for the registration of electrical
potentials of the brain
• Hans Berger (1929)
• scalp EEG
• electrocorticogram (ECoG)
• stereoelectroencephalogram (SEEG)
• macro EEG
• micro EEG
Electroencephalography
• placement of electrodes: system 10 - 20
Electroencephalography
• attachment of electrodes during scalp EEG
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Electroencephalography
• alpha rhythm: frequency 8-13 Hz, noticeable with eyes
closed, in awake, healthy and mature
brain, especially in parietooccipital lobes
• beta rhythm: frequency 14-30 Hz, noticeable with open
eyes, sometimes constantly over
frontal area. Phenomenon of suppression
of the alpha rhythm by opening eyes –
alpha attenuation reaction (AAR).
• theta rhythm: frequency 4-7 Hz, noticeable in children, in
healthy adult only during waking sleep
stages
• delta rhythm: frequency 1-3 Hz, in neonates and infants,
in healthy adults only during deep
non-REM sleep
Electroencephalography
• EEG waves
Electroencephalography
• EEG record - example
Evoked potentials (EP)
• electrical manifestation of brain activity triggered by
external sensory stimulus
• evaluation of the functional state of the nerve pathway
• TYPES OF EP:
VEP (visual)
AEP (auditory)
SEP (somatosensoric)
MEP (motoric)
SSEP (stable)
ERP (cognitive)
Evoked potentials
• wave p300 (mean latency 300ms)