MORE than a century ago, Virchow1 pointed out the difficult problems often encountered when attempting to diagnose subdural hemorrhage. Unfortunately, not all of the problems have been solved.
The electroencephalogram now has become a valuable and practical supplement to the clinical neurologic evaluation for diagnosis of intracranial lesions, and it has been widely used for assessment of cerebral function after head injury. In 1940 Jasper and co-workers2 found low-amplitude activity in EEGs recorded from scalp areas overlying subdural hematomas; in the same year Walter3 reported the occurrence of abnormal slow (delta) activity overlying epidural hematomas. Since that time, most investigators have found a high proportion of abnormal EEGs associated with either subdural or epidural hematomas,4,5 but there has been disagreement regarding the relative importance of the different types of EEG abnormality for diagnosis and localization of these lesions. Some authors6-12 have emphasized the localizing