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

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.