EEG in the elderly: seizures vs. syncope.

The EEGs of elderly patients with a definite seizure disorder (161 patients; 302 EEGs) were compared to patients with "syncope" (122 patients; 133 EEGs), especially to determine if the latter patients were sufficiently similar to the seizure patients that the syncope could be viewed as a seizure phenomenon. The two groups were similar only by the predominance of females in both groups (61-62%) and otherwise were very different. The seizure group had a higher incidence of (1) etiology (83 vs. 39%), (2) epileptiform discharges (93 vs. 49%), with a different location, more often parasagittal, and different number often with active or very active foci, (3) frontal slow waves, (4) more severe slow wave abnormalities, (5) slower background frequencies, that were less well organized and developed and (6) abnormal records. The conclusion is that the syncope patients as a group are usually not simply seizure patients. Regardless of etiology, the patients with "syncope" (33% with cerebrovascular and 21% cardiac etiologies) showed nearly a 50% incidence of epileptiform discharges, demonstrating a complex interrelationship between cardiac and cerebral mechanisms, which are discussed. The conclusion is that epileptiform activity in elderly patients with syncope is likely to be mildly epileptogenic, and may require additional cardiovascular mechanisms to generate an attack of unconsciousness.