[Correlations between intracranial pressure variations and EEG changes in patients with cranial trauma (author's...

Polygraphic studies were performed over periods of 14 to 76 hours in 30 patients with reccent closed cranial injuries. Correlations between ICP and EEG findings were rarely found (3/16) in cases of cerebral dysfunction of mesodiencephalic or lower levels, where both ICP and EEG were usually stable. Correlations are regularly found in diencephalic or higher (10/14) levels and their presence is of favourable prognostic significance. Generally, delta waves at 1,5-2 cs, high in amplitude (type A) accompany reduced or low ICP levels,while a rapid and low voltage tracing (type B) is associated with raised or high levels of ICP. In the latter cases, a very slow (0.5 cs) and low in amplitude tracing (type C) can progressively replace the type B. The classical periodic or alternating tracing associates alternate sequences of type A and B and is observed simultaneously with type B pressure waves. These correlations are analogous with those observed during the evolution of intracranial tumors or hydrocephalus. The EEG modifications are probably related more to the pathological lesion than to a direct action of fluctuations in ICP.