ACNS Guideline 1

Question 1

What is the minimum number of EEG channels required for clinical recording?

Answer 1

Sixteen channels.

Question 2

What EEG electrode system is officially recommended by the IFCN?

Answer 2

The 10–20 system.

Question 3

What materials are best for EEG electrodes?

Answer 3

Silver-silver chloride or gold disk electrodes.

Question 4

What is the acceptable impedance range for modern EEG equipment?

Answer 4

Up to 10 kOhms, but balanced impedances are optimal.

Question 5

What is the recommended duration for a baseline EEG recording?

Answer 5

At least 20 minutes of artifact-free recording.

Question 6

What should be included in an EEG patient data sheet?

Answer 6

Name, age, date/time, technologist initials, indication for EEG, last seizure, meds, skull defects, medical history.

Question 7

What is the function of the 60 Hz (notch) filter?

Answer 7

To reduce electrical interference when other methods fail.

Question 8

What are needle electrodes not recommended for?

Answer 8

Routine clinical use

Due to patient discomfort, risk of injuries, and higher impedances compared to cup electrodes.

Question 9

What are subdermal needle electrodes (SNE) or wire electrodes (SWE) used for?

Answer 9

Prolonged recording of EEG in stuporous or comatose patients

In situations where cup electrodes are not feasible.

Question 10

What system is officially recommended by the IFCN for EEG electrode placement?

Answer 10

The 10 to 20 System

It is the most commonly used system and should be used universally.

Question 11

What is the undesired term used when head measurements have not been made in electrode placement?

Answer 11

Modified 10 to 20 System

The term ‘estimated 10 to 20 placement’ is more appropriate.

Question 12

What should be placed and connected to the jackbox during EEG recording?

Answer 12

An isolated ground electrode

Prevents dangerous currents from passing.

Question 13

What is the acceptable range for interelectrode impedances in modern digital EEG recording?

Answer 13

Up to 10 k Ohms

Optimal recording requires balanced impedances.

Question 14

What should be checked as a routine pre-recording procedure?

Answer 14

Interelectrode impedances

To ensure proper recording conditions.

Question 15

What is the minimum information that should be included in the EEG record?

Answer 15

Name and age of the patient, date of recording, identification number, name/initials of the technologist

Essential for accurate medical and legal documentation.

Question 16

What should be done at the beginning of every EEG recording?

Answer 16

Appropriate calibrations

Includes square wave calibration for stability.

Question 17

What should the sensitivity of the EEG equipment for routine recording be set at?

Answer 17

5 to 10 mV/mm of trace deflection

A common initial sensitivity is 7 mV/mm.

Question 18

What can happen if the sensitivity is set less than 10 mV/mm?

Answer 18

Significant low-amplitude activity may become undetectable

High sensitivity can obscure normal EEG activity.

Question 19

What is the role of filtering in digital recordings?

Answer 19

Filtering occurs at two levels: analog filters in the amplifier and digital filters before display

Proper use is crucial for recognizing EEG abnormalities.

Question 20

What is the recommended low-frequency filter setting for standard recordings?

Answer 20

No higher than 1 Hz

Vital to prevent loss of pathologic activity information.

Question 21

What should the display duration be for routine EEG recordings?

Answer 21

10 to 20 seconds/page

Corresponds to a paper speed of 30 mm/second.

Question 22

What is the minimum duration for the baseline record in EEG?

Answer 22

At least 20 minutes of technically satisfactory recording

Longer recordings are encouraged for better detection of abnormalities.

Question 23

What should the recordings include regarding the patient’s eyes?

Answer 23

Periods when the eyes are open and closed

This helps assess the effect of stimuli on the EEG.

Question 24

What should be the distance of the lamp during photic stimulation?

Answer 24

At least 30 cm from the patient’s face

Performed in dimmed lighting.

Question 25

What is the minimum duration for hyperventilation in EEG recordings?

Answer 25

Minimum of 3 minutes ## Footnote Followed by continued recording for at least 1 minute.

Question 26

What should be performed before hyperventilation or at least 3 minutes after?

Answer 26

Photic stimulation ## Footnote Photic stimulation is important for accurate EEG assessment.

Question 27

Under what conditions should hyperventilation be routinely used?

Answer 27

Unless contraindicated by medical reasons ## Footnote Examples include recent intracranial hemorrhage, significant cardiopulmonary disease, and patient inability to cooperate.

Question 28

For how long should hyperventilation be performed?

Answer 28

A minimum of 3 minutes ## Footnote Recording should continue for at least 1 minute after cessation of overbreathing.

Question 29

What must be recorded before hyperventilation begins?

Answer 29

At least 1 minute of recording with the same montage ## Footnote This helps evaluate the effects of the activation technique.

Question 30

What additional recording should be included on one EEG channel?

Answer 30

A single-channel electrocardiogram (ECG) ## Footnote This is helpful for assessing spikes, sharp waves, or artifacts.

Question 31

What are photic stimulation and hyperventilation intended to elicit?

Answer 31

Epileptiform discharges and potentially seizures ## Footnote Patients should be informed about this possibility in advance.

Question 32

When should sleep recordings be performed?

Answer 32

Whenever possible, but not to the exclusion of the waking record ## Footnote Sleep recordings provide additional information about epileptiform discharges.

Question 33

What effect does sleep deprivation have on EEG results in patients with epilepsy?

Answer 33

Increases the frequency of detection of epileptiform discharges ## Footnote This can occur even during wakefulness.

Question 34

What should the technologist note on the EEG recording?

Answer 34

The patient's level of consciousness and any changes thereof ## Footnote This includes commands, movements, and seizure activity.

Question 35

What stimuli should be applied systematically during recordings for stuporous or comatose patients?

Answer 35

Visual, auditory, and somatosensory stimuli ## Footnote Responses or failures to respond should be noted closely in time.

Question 36

Who is responsible for recognizing patterns associated with different states of consciousness?

Answer 36

The electroencephalographer ## Footnote Observations by the technologist can provide interpretative value.

Question 37

What is essential for assessing awake background activity?

Answer 37

Ensuring the patient is maximally alert for part of the record ## Footnote This facilitates better EEG assessment.

Question 38

What should special procedures that are of some risk to the patient be carried out in?

Answer 38

The presence of a qualified physician and adequate resuscitation equipment ## Footnote Informed consent is also required.

Question 39

Who interprets the EEG after the recording is completed?

Answer 39

A neurophysiologist ## Footnote This should be done in a timely manner.

Question 40

What critical results should the technologist notify the interpreting physician about?

Answer 40

Presence of electrographic or clinical seizures and significant clinical events ## Footnote Timely notification is crucial for patient care.

Question 41

What do EEGs for the evaluation of cessation of cerebral function require?

Answer 41

Special procedures and extraordinary precautions ## Footnote Refer to specific guidelines for these situations.