[Electroencephalogram study of 52 cases following subarachnoid hemorrhage (author's transl)]

During the past nine years the authors have seen 140 cases of ruptured intracranial aneurysm. In order to assess the EEG abnormalities in the chronic period after SAH, 45 patients were examined with 108 serial EEG recordings. Cases of early death were excluded from this study. Seven cases of SAH of unknown origin were also examined as a control group. Range of age was from 28 to 79 years. All of these patients except one were able to return to their previous activities. Results and conclusion were as follows. (1) The period of EEG study varied from a few weeks to nine years after SAH with the average being ten months. (2) The overall incidence of abnormal EEG was 82.4% in Group A (aneurysm) and 83.3% in Group B (unknown origin). (3) EEG abnormalities were divided into two patterns: focal slow wave (sporadic, polymorphous theta and delta wave) and focal spike, located mainly in the frontal and/or temporal areas. (4) Symptomatic epilepsy occurred in 6 cases of this series (13.3%) with onset from 8 months to 3 1/2 years after SAH. (5) Recent papers on microsurgical treatment of intracranial aneurysms have reported excellent results. Few studies, however, have dealt with EEG in the chronic period after SAH. The importance of EEG in the follow-up study of SAH is stressed because of the high incidence and long persistence of EEG abnormalities and because of the occurrence of epilepsy after SAH.