Do occasional brief seizures cause detectable clinical consequences?

Seizures, particularly when prolonged or frequent, have been associated with a variety of adverse outcomes. However, epidemiological data provide little evidence for adverse effects of isolated brief seizures per se. Even the animal data is mostly for prolonged or frequent seizures. Febrile seizures lasting <10 min have not been associated with adverse seizures or cognitive outcomes. Treating either febrile seizures or other acute symptomatic seizures does not reduce the risk of subsequent epilepsy. In subjects with a first unprovoked seizure, seizure duration does not influence recurrence risk. Furthermore, treatment after a first unprovoked seizure reduces recurrence risk, but does not alter long-term prognosis. In epidemiological studies of newly diagnosed epilepsy, the number of seizures prior to therapy does not influence prognosis. There are a variety of specific epilepsy syndromes associated with poor cognitive outcomes and with progressive loss of function. However, the poor outcomes in these syndromes do not appear to be the result of seizures per se but rather to the specific syndrome and to the frequent interictal spike activity seen in these patients. Antiepileptic drugs, while effective in reducing seizure recurrence are also associated with a variety of potential adverse effects. On a risk-benefit basis, the available epidemiologic data do not justify starting treatment after the first seizure to attempt to influence long-term prognosis.