Classification

Description

Benign

Absence of all malignant features stated below (i.e., a continuous EEG of normal amplitude >20µV +/- reactivity).

Malignant

Malignant periodic or rhythmic patterns (abundant periodic discharges; abundant rhythmic polyspike-/spike-/sharp-and-wave; unequivocal electrographic seizure).

Malignant background (discontinuous background; low-voltage background; reversed anterior-posterior gradient).

Unreactive EEG (absence of background reactivity or only stimulus-induced discharges).

Highly Malignant

Suppressed background without discharges (<10µV).

Suppressed background with continuous periodic discharges.

Burst suppression with or without discharges.