Alpha waves (8 – 13 Hz)
Waking state of the normal adult
Predominant in drowsiness. Theta and alpha are equally dominant in children but as children get older, theta decreases and becomes more intermittent
Beta EEG (14 – 30 Hz)
Predominant in drug-induced sleep from barbiturates, with therapeutic levels of antidepressants and with the majority of benzodiazepines, such as Valium
Delta EEG (0.5 – 3 Hz)
Primary frequency found in the sleeping adult
Burst suppression EEG
This abnormal pattern can be seen following cardiac arrest and anesthesia and/or barbiturate intoxication
Seizure activity
This pattern is suggestive of epilepsy. Most seizures in the ICU are silent and can only be detectable with EEG
PLEDS (Periodic Lateralized Epileptiform discharges)
Transient pattern often seen following a cardiac arrestor respiratory event