Reversible profound depression of cerebral electrical activity in hyperthermia

Transient major reduction of EEG activity in an hyperpyrexic patient (rectal temperature 42.5 degrees C) and transient isoelectric ECoG during accidental hyperthermia (rectal temperature 41.8 degrees C) in a Rhesus monkey are reported. Since recovery of electrocortical activity occurred in both instance this implies that in hyperthermia, as well as in hypothermia, an isoelectric EEG may not indicate irreversible brain damage.