Temperature Effects on the Electroencephalogram

Abstract

.The normal range of oral temperatures in humans varies from 92.2° F (36.2° C) to 99.0° F (37.2° C). Changes in body temperature can be directly induced by external factors, or may result from internal processes, i.e. infection or loss of temperature control. The EEG findings in hypo- and hyperthermia reflect not only temperature effects but also other processes that are happening concurrently. The Harvard criteria for “brain death” require a body temperature of at least 90° F (32.2° C) although cerebral activity has been recorded at much lower temperatures. Hypothermia is used clinically to protect the brain during decreased or absent cerebral circulation, usually during cardiac surgery. Hyperthermia can also cause a decrease in EEG activity, although not as dramatic as that seen with hypothermia. Hyperthermia is used clinically in oncology as an adjunct to chemotherapy.