The Electro-encephalogram in Acute Head Injuries.

IN a series of papers published ten years ago Berger reported abnormally slow waves in the electro-encephalogram (e.e.g.) of patients with diverse intracranial abnormalities. This work has already been adequately reviewed (Jasper, 1937, Walter, 1938). Since then these abnormally slow changes in electrical potential have been investigated in relation to tumours, abscesses, and other local lesions (Walter, 1936, 1937), high intracranial pressure (Williams, 1939), intoxications (Gibbs, Gibbs and Lennox, 1937) and degenerative diseases (Williams and Gibbs, 1939). Similar slow waves are associated with such general cerebral disturbances as the epilepsies (Gibbs, 1939), the psychoses (Hoagland, Cameron and Rubin, 1937) and abnormal personalities (Lindsley and Cutts, 1940). No such specific characteristics as have been described in relation to the epilepsies have been found in the abnormal slow waves resulting from demonstrable cerebral damage. It appears, on the contrary, that most conditions detrimental to cerebral activity are associated with suppression of the normal frequencies and a concomitant increase in the slower components of the frequency spectrum of the e.e.g. (Gibbs, Williams and Gibbs, 1940). These abnormal conditions range from the genetic abnormality of unstable personalities and epileptics to cerebral destruction by tumours or infection, and include transitory changes in blood constituents or cerebral blood flow. The abnormally slow waves are therefore non-specific, but there appears to be a direct relationship between their number, size, and period and the severity of cerebral change. During an earlier investigation of intracranial abnormalities (Williams, 1939) an attempt was made to correlate electro-encephalographic changes with different pathological states, and during the course of this work it was found that cerebral trauma produced abnormally slow waves, similar to those already mentioned. These changes seemed to be more variable in extent and degree, and to have a less constant relationship to the apparent severity of the lesion, than did similar changes in other abnormal states. Head injuries are notorious