Alpha coma: unresponsive to external stimuli, 3 days after cardiopulmonary arrest, indicates a poor prognosis, Can also be seen in brainstem strokes and drug overdose,
- Posterior-dominant alpha coma pattern may be seen in setting of a brainstem lesion.
- Anterior-dominant (or generalized) invariant alpha coma pattern may be seen in setting of a global insult such as cardiac arrest or bilateral thalamic infarcts
Beta coma: Beta activity superimposed on delta, Seen in drug overdose(often barbiturate or benzodiazepine intoxication)
Spindle coma: Resembles sleep EEG but little response to afferent stimuli, Results from head trauma, brainstem lesions, drugs, hypoxia, Associated with good prognosis