EEG in Encephalopathy and Coma

.Despite advances in neuroimaging, the EEG remains extremely helpful in the evaluation of encephalopathy and coma. This review discusses a variety of encephalopathies and associated EEG findings. These include metabolic disturbances, such as hepatic or renal dysfunction, which are often characterized by slowing of background rhythms and triphasic waves. Hypoxia and drug intoxications can produce a number of abnormal EEG patterns such as burst-suppression, alpha coma, and spindle coma. Patients can be encephalopathic because of ongoing epileptic activity with minimal or no motor movements. This entity, nonconvulsive status epilepticus, is difficult to diagnose in obtunded/comatose patients. An EEG, which is required to verify the diagnosis, can also help monitor trreament.