FACTORS OF IMPORTANCE FOR THE DEVELOPMENT OF EPILEPSY IN PATIENTS WITH CEREBRAL INFARCTION

The value of EEG in the investigation of postapoplectic epilepsy

During the 5 years 1979-1983 61 patients within the county of Frederiksberg developed postapoplectic seizures after the age of 60. Of these patients EEG was performed on 48. These EEG's were compared to the EEG's from 25 patients of the same age with epilepsy due to cerebral tumors 33 patients with acute stroke and 24 patients with stroke sequelae who had not experienced seizures. Slow wave activity and foci were seen more often among patients with acute stroke than among patients with postapoplectic seizures whereas paroxysmal activity occurred less often in patients with acute stroke than among patients with postapoplectic seizures patients with stroke sequelae and patients with seizures due to cerebral tumours. Patients with stroke sequelae with proven hemispheric localization had focal abnormalities more often than patients with postapoplectic seizures but apart from this EEG difference between patients with postapoplectic seizures and patients with stroke sequelae or seizures due to brain tumours were not found. In 12 of the patients with postapoplectic seizures and in 20 of the patients with stroke sequelae without seizures EEG at the time of the acute stroke was available. Differences between patients with and patients without seizures were not found neither at the time of the acute stroke nor at the time of readmission due to stroke sequelae or due to onset of seizures. It is concluded that a routine EEG is without value in the diagnosis of postapoplectic seizures in the elderly.

Etiology of seizures in the elderly

Our study covered a 5-year period, and included all patients within a well-defined area who developed seizures after age 60 years. The dominant cause of seizures was a previous stroke, accounting for 32% of all cases. Tumors accounted for 14%, and the cause of seizures remained unknown in 25%. Seizures were recurrent in greater than 80% of patients with first seizure greater than 6 months after stroke. Fifteen of 21 patients with tumors had metastatic tumors. Of the six patients with primary brain tumors, five had malignant gliomas and one had a meningioma. We conclude that epilepsy with onset after age 60 years is more often symptomatic than is epilepsy in younger patients; since seizures were the first sign of a central nervous system (CNS) disease in half of the patients with brain tumors, careful investigation is necessary to reach a correct diagnosis.