EEG Electrocerebral Inactivity and Brain Death Determination

Question 1

According to American Clinical Neurophysiology Society (ACNS) and AAN guidelines, what is the minimum sensitivity required when recording an EEG to assess for electrocerebral inactivity (ECI)?

Accepted Answer

2 µV/mm

Answer

AAN/ACNS guidelines require a minimum sensitivity of 2 µV/mm (equivalent to ≤2 µV/mm) during ECI recordings so that very low-amplitude cerebral activity is not missed. Standard clinical sensitivity (7 µV/mm) would be insufficiently sensitive for this purpose.

Question 2

AAN guidelines for ECI recordings require a minimum interelectrode distance of at least how many centimeters to avoid missing low-amplitude activity between nearby electrodes?

Accepted Answer

10 cm

Answer

A minimum interelectrode distance of 10 cm is mandated so that small potential differences across brain tissue are not masked by electrodes placed too closely together. Shorter distances increase the risk of amplitude cancellation and may falsely suggest ECI.

Question 3

Which of the following must be documented and excluded before an EEG can be interpreted as confirming electrocerebral inactivity?

Accepted Answer

Core body temperature above 32°C, absence of CNS depressants, and no severe metabolic disturbance

Answer

Before ECI can be considered confirmatory for brain death, reversible causes must be excluded: core temperature must be ≥32°C (hypothermia suppresses EEG), CNS depressant drugs must be absent or below therapeutic levels, and severe metabolic disturbances (e.g., extreme hypoglycemia) must be ruled out.

Question 4

During a brain death EEG, the technologist applies a painful stimulus (sternal rub) and shines a bright light in the patient's eyes. The purpose of these maneuvers is to assess:

Accepted Answer

EEG reactivity to external stimulation

Answer

Reactivity testing is a required component of an ECI study. Any change in the EEG in response to painful, auditory, or visual stimulation indicates residual cortical function and rules out true ECI. The absence of reactivity, combined with flat tracing at high sensitivity, supports the ECI determination.

Question 5

A flatline EEG tracing recorded at 2 µV/mm sensitivity is most likely artifactual rather than true ECI if which finding is present?

Accepted Answer

Activity that disappears when the technologist lifts the patient's arm off the bed

Answer

If apparent flatline activity disappears when a potential movement artifact source (such as the patient's arm resting against the bed or equipment) is removed, the 'activity' was movement or ECG artifact rather than true cerebral electrical potentials. True ECI persists regardless of patient position adjustments.

EEG - Electroencephalography Practice Test

EEG - Electroencephalography Practice Test

EEG Electrocerebral Inactivity and Brain Death Determination