The EEG mapping in the evaluation of patients with late onset epilepsy.

In 62 patients with late onset epilepsy the findings of EEG mapping routine EEG and CT were compared. Forty four patients had generalized, 18 partial seizures. In 39 patients (63%) EEG mapping revealed focal changes but only in 24 patients (39%) using routine EEG alone. Thus the EEG mapping showed focal abnormalities significantly more often and this could be demonstrated in the separated groups of patients with generalized or partial seizures as well. Lesions in CT occurred in 39 patients (63%). The focal abnormalities in EEG mapping were significantly related to the lesions in CT. Moreover focal changes corresponding to CT lesions were obtained by means of EEG mapping in 32 patients (82%) but only in 20 patients (51%) using routine EEG and in that way the EEG mapping could indicate focal lesions in CT significantly more often than routine EEG. Regarding etiology this was especially seen in the group with vascular origin of epilepsy.