Clinical and radiological correlates of EEG in the late phase of head injury: a study of 515 Vietnam veterans.

Electroencephalograms were obtained in 515 Vietnam veterans 12-16 years after penetrating head injury, and the results were correlated with a variety of clinical and radiological parameters. Forty-two percent of EEGs were abnormal; 9% disclosed epileptiform findings (EF). EF correlated highly (P = 0.0001) with the extent of brain volume loss (defined by CT), posttraumatic epilepsy, and organic mental disorder. 'Seizure persistence' was higher and duration of posttraumatic epilepsy was longer in patients with 'prominent EF.' All patients with anterior temporal or central spike foci experienced posttraumatic seizures. Focal slowing correlated significantly with focal neurologic deficits such as hemisensory deficit or hemiparesis and Broca's aphasia as well as with seizures and residual organic mental disorder. Total or near total recovery from original hemiparesis was noted in 70% of the patients with normal EEG and 32% of the patients with focally slow tracings.