Computerized transverse axial tomography (CTAT) in the diagnosis of epilepsy.

99 patients with late epilepsy were investigated in our EEG laboratory. In intervals of maximal 100 days (averaged 23 days) a waking EEG recording and a CTAT were carried out. The average age was 43. 62.5% of the pathological CTATs were found in partial seizures with elementary symptomatology. In patients with generalized seizures the diagnosis of symptomatic epilepsy could be made in 20 cases (34%) with the help of computerized tomography. Generalized seizures were related to tumors only in 8.5% in our case material. In 20 of 99 EEGs in our patients there was a continuous delta wave focus, 12 of these with epileptogenic activity. Of these 20 patients, 18 showed a pathological result in computerized tomography. Eight tumors or metastases, 8 cases of atrophy (7 local and 1 diffuse) as well as 1 case of encephalitis could be diagnosed. 12 EEGs showed continuous or intermittent theta wave foci. Computerized tomography never gave a pathological finding in these patients. If one compares the results of CTAT and EEG in cases of tumor, the agreement between positive tomography and the pathological EEG is very high (97%): 33 positive CTATs comapred with 31 positive EEGs. Our investigations with computerized tomography show organic findings in 34 of 99 epilepsies, that is about 34%.