1. SCHEMATIC DIAGRAM OF AN EEG MACHINE

2. EEG Transducer(Recording set up)

3. EEG Transducer(Recording set up)
Electro encephalography - study of electrical activities of the brain.
Electrodes attached to different parts of the skull of a patient.
8 channel EEG recorder:-
Patient cable consists of 21 electrodes
Electrodes connected to selector in groups of 8- Montage of electrodes
Right ear electrode  reference electrode right brain electrodes
Left ear electrode  reference electrode left brain electrodes

4. EEG Transducer(Recording set up)
Interference problem is reduced by differential amplifier(preamplifiers)
Filter bank:- consists of appropriate filters to select different types of brain waves.
Output can be given to 8-channel pen recorder, display unit, computer storage memory for further processing.
Evoked Potential:- Measure of the “disturbance” in the EEG pattern that results from external stimuli.
Time delay between stimulus and response can be measured in signal processing unit.

5. BRAIN WAVES
Alpha waves-normally persons Awake and alert ,occipital region.
Beta waves- recorded from parietal and temporal regions.
Theta waves- recorded from parietal and temporal regions of Children, adults- emotional stress
Delta waves-deep sleep, premature babies, every serious organic brain diseases.