Effects of topiramate on neurophysiological and neuropsychological tests in migraine patients.

Topiramate (TPM) is a antiepileptic drug that has multiple mechanisms of action. It is effective as a monotherapy for migraine prophylaxis. Unfortunately, TPM can frequently cause adverse effects, such as cognitive dysfunction. The present study examines the neuropsychological and neurophysiological effects of TPM in 35 consecutive migraine patients above 18years of age. The TPM dose was started at 25mg/day and increased by 25mg/week, until reaching the maximum dose of 50mg twice daily in the fourth week. Patients were evaluated for development of side effects of the medication and for its effectiveness on migraine. The Wechsler memory scale was used for neuropsychological evaluation and cognitive evoked potentials were used for neurophysiologic evaluations. Analyses of repeated measures show that visual analog scale pain values, as well as migraine attack frequency and headache duration, were decreased significantly during the study. The amplitudes and latencies of P300 did not change. The results of this study show that 100mg TPM is effective in the prevention of migraine headache and in reducing severity of attacks. Patients' cognitive complaints are frequent in the first month and decrease in the following month. Despite these complaints, only the attention section of the visual memory section of the Wechsler memory scale was affected - other sections were not affected. Also, P300 study did not reflect changes appropriate to these cognitive complaints.