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.

EEG and epilepsy in the elderly compared to a younger group

EEG in epilepsy in the elderly (onset > 60 yrs) was investigated (161 patients--302 EEGs) and was compared to a group of younger patients (onset 20-59 yrs) matched for sex ratio (also 161 patients--296 EEGs). In the elderly, the frequency of the background rhythm was decreased, as was the rhythmicity and amplitude. Complex partial attacks were twice as often seen in the older group, but generalized tonic-clonic seizures were more than three times as often in the younger group. The major etiology in the elderly was cerebrovascular disease, but brain tumors were found in nearly one quarter, while head injury, drug abuse, and AVM were more often seen in the younger patients. The first EEG was positive for epileptiform activity in 83%, later at 92-93% in both groups, emphasizing adequate sleep records. Although temporal lobe abnormalities were most often seen, frontal lobe discharges and slow waves were significantly more often noted in the elderly. As an example of the prominence of epileptiform activity in some elderly, PLEDs and very many discharges were seen mainly in the older group, which less often showed only rare discharges.