FREE BRPT Application of Electrodes and Sensors using the 10-20 System Questions and Answers

Question 1

According to the International 10-20 System, how is the location of the C3 electrode determined?

Accepted Answer

20% of the nasion-inion distance to the left of the Cz point.

Answer

10% of the head circumference superior to the left preauricular point.

Answer

20% of the distance from the nasion to the inion, measured from the nasion.

Answer

20% of the distance from the left preauricular point to the right preauricular point.

Question 2

What is the standard placement for the right electrooculogram (ROC) electrode according to AASM guidelines?

Accepted Answer

1 cm below and 1 cm out from the outer canthus of the right eye.

Answer

Directly on the outer canthus of the right eye.

Answer

2 cm above the inner canthus of the right eye.

Answer

On the supraorbital ridge of the right eye.

Question 3

What is the AASM recommended maximum impedance level for EEG and EOG electrodes?

Accepted Answer

5 kΩ

Answer

1 kΩ

Answer

10 kΩ

Answer

50 kΩ

Question 4

In a standard polysomnography montage, the derivation 'C4-M1' refers to the electrical potential difference between which two points?

Accepted Answer

The C4 electrode and the left mastoid (M1) process.

Answer

The C4 electrode and the ground electrode.

Answer

The C4 electrode and the right mastoid (M2) process.

Answer

The C3 electrode and the left mastoid (M1) process.

Question 5

When placing the three chin EMG electrodes, what is the primary physiological activity being measured?

Accepted Answer

Muscle atonia associated with REM sleep.

Answer

Jaw clenching and bruxism.

Answer

Swallowing and respiratory effort.

Answer

Snoring vibrations.

Question 6

If a patient has a lot of hair and measuring the nasion-inion distance is difficult, what is a common procedural step to ensure accuracy?

Accepted Answer

Use a piece of string to follow the scalp contour, then measure the string.

Answer

Estimate the distance based on the patient's head size.

Answer

Use a flexible tailor's tape measure and press down firmly.

Answer

Place the electrodes based on visual landmarks only.