Long-term prognosis in intractable epilepsy: Looking beyond a year

Abstract

Introduction: There is good evidence to suggest that approximately one third of new-onset epilepsy patients will be refractory to medication and that further medication trials in these patients is unlikely to result in complete control, at least in the short term [1]. Information from trials of new antiepileptic drugs (AEDs) in refractory patients supports this notion. Patients in these trials have typically failed five or more other anticonvulsant drugs, with continued seizure frequency of at least three per month. The new drug is added to the patient’s baseline AEDs, with careful accounting of the impact on seizure frequency. Even in the relatively short period of 2 to 3 months typically included in the trials of new AEDs, fewer than 10% of patients typically become completely seizure free [2,3]. It is, therefore, clear that in patients with continued seizures after failure of several AEDs that the addition of another drug, or even simply continuing the present one, may result in improvement but not resolution of seizures in the short term. This important information is, appropriately, something of a rallying cry for awareness of intractability in epilepsy. Patients failing initial AED therapy should be referred to epilepsy centers for definitive diagnosis and evaluation for alternative treatments, especially epilepsy surgery, which (also in the short term) carries a much higher rate of seizure freedom [4,5]. But what about the long term? There is a relative paucity of prospective studies following patients for years or decades. An ongoing study of epilepsy surgery is addressing this question after surgical treatment, but what of the approximately 30% of epilepsy patients who are deemed refractory and who do not receive surgery? Two recent studies give tantalizing, though perhaps limited, information regarding long-term prognosis in refractory epilepsy [6,7].