Long-term cognitive outcomes in patient with epilepsy

In contrast to short-term cognitive outcomes, long-term cognitive outcomes (over 5 years) has been scarcely assessed so far. Yet, predicting long-term outcomes at any time point of the epilepsy, from initial diagnosis, to medically intractability is very important for therapeutic decision-making, patient information, and orientation. Assessing long-term cognitive outcomes in patients with epilepsy would ideally require longitudinal studies and a comparison with a healthy controls group. This issue has been addressed extensively, but with controversial results. However, there is a general consensus about the fact that cognitive outcome is not the same in all groups of patients with epilepsy. Possible prognostic factors include age at onset, duration of epilepsy, syndrome and etiology, seizure outcome and therapeutics. The multiplicity of factors makes it very difficult to assess their relative weight in individuals. Although long-term cognitive outcome studies are scarce, this issue has been specifically studied in newly diagnosed epilepsies and in focal drug-resistant epilepsies. In the first clinical setting, i.e. newly diagnosed epilepsy, it appears that cognitive deficits are already present at epilepsy onset in a significant proportion of patients but seem to remain stable over time. In focal drug-resistant epilepsies, cognitive deficits (mainly verbal memory) were generally shown to remain stable provided that seizures were controlled either by medication or by surgery. Beyond the possible correlation between seizure and cognitive outcome, no causal link however has been demonstrated between these two important outcomes.