FREE EEG AND STUDY GAMES ABOUT EEG MONTAGES

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FREE EEG AND STUDY GAMES ABOUT EEG MONTAGES

EXAM QUESTIONS

Actual Qs and Ans Expert-Verified Explanation

This Exam contains:

-Guarantee passing score -31 Questions and Answers -format set of multiple-choice -Expert-Verified Explanation

Question 1: What are the 2 different types of montages that are used?

Answer:

• Monopolar (Referential)

• Bipolar

Question 2: How are potentials localized on a referential montage?

Answer:

Amplitude.

Question 3: What is a transverse bipolar montage?

Answer:

This montage has derivations going from left to right across the head. Channels are usually arranged from front to back.

Question 4: What is the advantage of a CAR montage?

Answer:

Equal interelectrode distances between the two hemispheres.

Question 5: What is a montage?

Answer:

Also called arrays, montages are combinations of multiple derivations (electrode recording combinations).

Question 6: What are the advantages to an ear reference montage?

Answer:

• Little to no cancellation when using a contralateral ear montage due to long interelectrode distances.

• Long interelectrode distances allow potentials to appear higher amplitude than usual, making it easier

to read.

Question 7: What is an average reference montage?

Answer:

This montage adds all the activity of all electrodes together in input 2 at every amplifier to serve as a reference for each of the individual electrodes in input 1.

Question 8: What are the disadvantages to a CAR montage?

Answer:

• Contamination

• Distortion of brain signals - if the CAR becomes part of the electrical field, the electrodes nearest will

cancel out and those farthest will give false localization.

Question 9: What is important about the placement of the reference?

Answer:

The reference must be placed in an electrically quiet spot on the patient. If placed in an electrically busy area, there will be contamination of all the other leads.

Question 10: What are the 3 good montage requirements?

Answer:

• Left hemisphere derivations over the right.

• Derivations are organized in an anatomical order (ant to post).

• Common electrode reference montages should have long interelectrode distances.

Question 11: What is a laplacian montage?

Answer:

This montage is similar to the common average reference, but instead on refers one electrode to the nearest neighbouring electrodes. Creates a local weighted average reference.

Question 12: What is the advantage of a Cz reference montage?

Answer:

Equal interelectrode distances.

Question 13: What are the disadvantages to an ear reference montage?

Answer:

• Contamination with EKG potentials.

• Cancellation (when ipsilateral) due to reference becoming a part of the electrical field.

Question 14: What is reference contamination?

Answer:

This occurs when the reference is no longer neutral, meaning it has been obscured with an overriding potential, whether mechanical or biological.

Question 15: What is the disadvantage of a laplacian montage?

Answer:

Edge electrodes are not symmetrically surrounded by other electrodes and therefore, cannot be uniform for all input 1 electrodes.

Question 16: What is a bipolar montage?

Answer:

A montage that consists of an adjacent pair of electrodes of the 10-20 system of electrode placement.

Question 17: What are the advantages of a transverse montage?

Answer:

• Easy comparison of left and right hemispheres.

• Easy comparison of amplitude gradient between anterior and posterior head.

Question 18: What is the end of chain phenomenon?

Answer:

This occurs when potentials appear with greatest voltage in the last electrode in the chain of electrodes producing waveform deflections that are all in the same direction (no phase reversal).

Question 19: What is the advantage of a weighted average montage?

Answer:

It reduces the possibility of a widespread activity contaminating the reference.

Question 20: What can prevent contamination in an average reference montage?

Answer:

More electrodes contributing to the reference.

Question 21: What is the disadvantage of an average reference montage?

Answer:

If one electrode has a much higher potential than the rest of the electrodes, it will contribute much more to the reference causing contamination of the EEG.

Question 22: What are some types of bipolar montages that we use?

Answer:

• Longitudinal (anterior to posterior)

• Transverse (left to right)

Question 23: What are some types of referential montages that are used?

Answer:

• Common average reference

• Cz reference

• Ear reference (contralateral or ipsilateral)

Question 24: What is an advantage of a bipolar montage?

Answer:

Best for analysing low to medium amplitude waveforms that are highly localized.