EEG 10 - 20 electrode placement which help to technologist how to measure the placement.

1. Mohibullah Fazli Kakar
PT, NP Technologist
3rd
year medical student
FMIC; April 2018
Electroencephalography
10 – 20 system electrode placement

2. What is 10 – 20 system
An internationally recognized method that allows EEG
electrode placement to be standardized.
OR
The 10-20 System of Electrode Placement is a method
used to describe the location of scalp electrodes

3. The 10-20 system is based on the relationship between
the location of an electrode and the underlying area of
cerebral cortex.
Each site has a letter and a number or another letter to
identify the hemisphere location.
The letters F, T, C, P, and O stand for Frontal,
Temporal, Central, Parietal and Occipital.
Even numbers (2,4,6,8) refer to the right hemisphere
Odd numbers (1,3,5,7) refer to the left hemisphere.
The z refers to an electrode placed on the midline.
What is 10 – 20 system

4. Four Skull Landmarks:
Nasion
Inion
Left Pre auricular point‐
Right Pre auricular point‐
What is 10 – 20 system

5. Pre – Auricular point

6. Measuring FPz or Reference Electrode:
Measure the distance from nasion to inion
 measure 10% of all distance from nasion and mark for
Reference electrode in the front.
Measuring Oz:
Measure the distance from nasion to inion
 measure 10% of all distance from inion and mark for Oz
in the back.
What is 10 – 20 system
Note:
•Every 10% = 20%
•Every 10% / 2 = 10%

7. Measurement of CZ:
Measure the distance from FPz to Oz and divide/ 2 = CZ
Measurement of FZ:
Measure the distance form CZ – Ref
divide by 2 = Fz
Measurement of PZ :
Measure the distance from Cz – Oz divide / 2 = PZ
What is 10 – 20 system
FPZ

8. Measurement of FP1 and FP2:
Measure the distance head circumference and take 10% of all
measurement divide / 2 mark it:
On left side for FP1
On right side for FP2
Measurement of F7 and F8:
Measure the distance head circumference and take 10% of all
measurement
Mark 10% by measuring for every led
What is 10 – 20 system

10. Measurement of T3 and T4:
Measure the distance between pre – auricular points and cross
Cz
Mark 10% of the distance from left and right pre – auricular
points of ears.
Left for T3
Right for T4
What is 10 – 20 system

11. Measurement of T5 and T6:
Measure the distance head circumference and take 10% of all
measurement
Mark 10% by measuring for every led
FPz 10%  F7 10%  T3 10%  T5 10%
FPz 10%  F8 10%  T4 10%  T6 10%
What is 10 – 20 system

12. Measurement of F3 and F4:
Measure the distance from F7 – Fz / 2
Mark on the left for F3
Mark on the Right for F4
What is 10 – 20 system

13. Measurement of C3 and C4:
Measure the distance form CZ – T3 / 2 = C3
Measure the distance form CZ – T4 / 2 = C4
Measurement of P3 and P4:
Measure the distance from T5 – PZ / 2
Mark on the left for P3
Mark on the Right for P4
What is 10 – 20 system

14. Measurement of O1 and O2:
 Measure the distance head circumference and take 10% of all
measurement mark it:
On Left side for O1 = T5 10% = O1
On Right side for O2 = T6 10% = O2
What is 10 – 20 system