kursk state medical university

1. Electro-Encephalography
Swami Keshav (Group 9, 2nd year 3rd semester)
Kursk state medical university
Repalova Natalia Vladimirovna
Detail physiology of CNS

2. Electroencephalography (EEG) is a method to record
an electrogram of the electrical activity on the scalp that
has been shown to represent the macroscopic activity of
the surface layer of the brain underneath.
It is typically non-invasive, with the electrodes placed
along the scalp.
Electrocorticography, involving invasive electrodes, is
sometimes called intracranial EEG.

3. EEG measures voltage
fluctuations resulting from
ionic current within the
neurons of the brain.
Clinically, EEG refers to the
recording of the brain's
spontaneous electrical activity
over a period of time, as
recorded from multiple
electrodes placed on the
scalp.

4. Band Frequency (Hz)
Delta < 4
Theta ≥ 4 and < 8
Alpha ≥ 8 and < 14
Beta ≥ 14
Rhythm
• The rhythmic activity is divided into bands by
frequency.

5. DIAGNOSIS
An EEG is a test that detects abnormalities in your brain waves, or
in the electrical activity of your brain. During the procedure, electrodes
consisting of small metal discs with thin wires are pasted onto your
scalp. The electrodes detect tiny electrical charges that result from the
activity of your brain cells.
Two measurements are commonly used to analyse an EEG record:
amplitude, or size of the waves,
number of waves per second

7. An EEG might also be helpful for diagnosing or treating
the following disorders:
•Brain tumor.
•Brain damage from head injury.
•Brain dysfunction that can have a variety of causes (encephalopathy)
•Inflammation of the brain (encephalitis)
•Stroke.
•Sleep disorders.

8. ADVANTAGES
• Non – invasive & harmless
• Lower costs
• Portable
• High Temporal Resolution

9. DISADVANTAGES
• High noise ratio
• Not very exact measuring
• Skull weakness the electrical activity
• Low spatial resolution

10. Спасибо!!