[EEG in post-traumatic coma. Diagnostic and prognostic value (author's transl)].

This study concerns 1600 post-traumatic acute comas, who underwent combined clinical and EEG examinations. The EEG has been recorded accurately bedside several times a day throughout the acute stage. The obtained EEG patterns, generally considered to be polimorphous and extremely variable, can be classified into five basic groups corresponding to progressive deterioration of the cerebral electrogenesis: borderline, changeable, sleep-like, monotonous and silent. Borderline, sleep-like and changeable patterns, even though they indicate a varying degree of impairment of cerebral electrogenesis, prove nevertheless that the brain is capable of elaborating physiological rhythms and of modifying its activity in a spontaneous or evoked manner. True slow monotonous activity indicates an extreme degree of cerebral impairment; flattening, up to EEG silence, indicates the onset of brain death. Focal slowing and/or flattening, which often lacks surgical significance, is not considered in this classification. Focal or generalized irritative activity in the early stages, however, indicates a more severe condition. EEG has often proved to be an useful means supporting the diagnostic and prognostic value of clinical examination.