Abstracts

Premonitory symptoms are usually defined as phenomena occurring more than 30 minutes before the onset of epileptic seizures. So far, their meaning is unclear, unlike auras, they are, however, generally not regarded as a correlate of ictal epileptic activity. So far few data are available on their prevalence and to their semiologic characteristics as compared to auras in the same patient. This study investigated the prevalence and type of premonitory symptoms in epilepsy patients at three german tertiary referral centers. Questionnaires were handed out to a total of 500 unselected patients at the epilepsy centers of Freiburg, Kork, and Kleinwachau agreeing to participate. 415 patients had epilepsies classified as focal, 82 had epilepsies classified as primarily generalized. Patients were asked to report the presence of signs or symptoms preceding seizure for at least 30 minutes. If premonitory symptoms were present, they were asked to describe their nature. These data were related to the epilepsy syndrome and to seizure semiology. 35/500 patients (7.0 %) reported symptoms occurring more than 30 minutes preceding the onset of seizures. 30 patients had focal epilepsy (prevalence 7.2%), 5 had generalized epilepsy (prevalence 6.1%). The median of estimated time of premonitory symptoms preceding the seizure was 90 min (range 30 minutes - 24 hours).
Most common symptoms reported were restlessness, headache, feeling uncomfortable, nausea, disturbance of concentration, dizziness and tiredness.
In 17/35 patients also auras were reported; in three of them, symptoms were similar suggesting that they also suffered from prolonged auras. In the majority of patients, however, symptoms differed considerably. This cross-sectional study in patients at tertiary referral centers resulted in a frequency of premonitory symptoms well below previous reports which may be due to the fact that other studies did not investigate auras separately. Differences in semiology between premonitory symptoms and auras in the vast majority of patients suggest a different underlying pathophysiology.