What does the impedance check's odd/even error mean?

This error occurs when only the odd or only the even numbered channels are enabled or gelled using SAGA.

During an impedance check, the impedances are shown through color-coded indicators. When an odd/even error occurs, the color indicators of all electrodes turn pink and the impedance value is  5100 kΩ.

For the TMSi gel headcap, the Odd/Even error occurs when only the odd or only the even channels are gelled. When this error occurs, the color for the impedance check of all electrodes turns pink. To prevent this error, at least one odd (1, 3, 5 etc) and one even numbered channel (2, 4, 6 etc) connected to the subject should be gelled. Once both an odd and an even channel are gelled, the error should disappear.

For a water headcap, the same error occurs when only the odd or even water-based electrodes are wet.

When using a few channels, it could be that one of the even/odd channels is not making appropriate contact, which results in a similar error as well.

The table below shows the electrode position's channel number, to help find the odd and even numbered channels.

Channel #

Cap electrode position

 

Channel #

Cap electrode Position

Fp1

 

 33

AF7

FC3

 

 34

AF3

Fp2

 

35

AF4

F7

 

36

AF8

5

F3

 

37

F5

6

Fz

 

38

F1

7

F4

 

39

F2

F8

 

40

F6

FCZ

 

41

FC3

10

FC4

 

42

FCz

11 

CP3

 

43

FC4

12 

CPZ

 

44

C5

13 

M1

 

45

C1

14

T7

 

46

C2

15 

C3

 

47

C6

16

Cz

 

48

CP3

17

C4

 

49

CPz

18

T8

 

50

CP4

19

M2

 

51

P5

20

FT8

 

52

P1

21

FT7

 

53

P2

22

TP8

 

54

P6

23

TP7

 

55

PO5

24

P7

 

56

PO3

25

P3

 

57

PO4

26

Pz

 

58

PO6

27

P4

 

59

FT7

28

P8

 

60

FT8

29

CP4

 

61

TP7

30

O1

 

62

TP8

31

Oz

 

63

PO7

32

O2

 

64

PO8

 

Do you have further questions on this topic?

Contact ✉️ support@tmsi.com, ğŸ“ž+31 (0)541 539 013 or ğŸ“„ request support.