Impact of valproate and phenytoin on cognitive function in elderly patients: results of a single-blind randomized...

Thirty-eight patients (median age 77 years; range 62-88 years) with elderly-onset seizures were entered into a single-blind, randomized study designed to compare the impact of phenytoin (PHT) and valproate (VPA) on cognitive function. A stratified minimization program matched the two groups for age, sex, and seizure type. Attention, concentration, psychomotor speed, and memory were assessed twice before treatment (to minimize practice effects), at 6 weeks and (for patients remaining in the study) at 3 months, 6 months, and 1 year by an extensive battery of psychologic tests. Changes in cognitive function were minor, and some tended toward improvement. Contrary to expectation, there was little difference between PHT and VPA with regard to impact on cognitive function. Frequent noncognitive adverse effects were reported. Thus, we did not replicate the findings of previous literature. We conclude that antiepileptic drug (AED) monotherapy as used in our trial did not produce significant adverse cognitive effects. The choice of AED in the elderly may therefore be more influenced by consideration of other adverse effects.