Alcohol and the EEG

EEGs are often performed on patients with a history of alcohol abuse. Certain EEG findings are characteristic of an alcohol-associated condition, but there are no pathognomonic changes. Chronic alcoholism is associated with a high incidence of low voltage recordings, however a small number of non- alcoholic patients may also have low voltage EEGs. In mild, uncomplicated withdrawal, the EEG may be normal or may show only mild, diffuse slowing. In more severe withdrawal states, including delirium tremens, there is a higher incidence of slowing. EEGs in patients with generalized withdrawal seizures are predominantly normal or show minor amounts of slowing. Patients with previous focal seizures or head injuries, are likely to show focal or paroxysmal EEG changes. Photomyoclonic and photoconvulsive responses sometimes occur during alcohol-withdrawal states, but in recent years have become uncommon. Alcohol abuse leads to numerous secondary conditions such as hepatic encephalopathy, Wernicke-Korsakoff syndrome, dementia, focal brain injury, each of which may be associated with EEG changes. The EEG is helpful in evaluating cerebral function in a variety of alcohol-related conditions.