[Cognitive effects of therapy with topiramate in patients with refractory partial epilepsy]

Multiple studies have demonstrated that antiepileptic drug therapy may have consequences on cognitive function. Topiramate (TPM) is a new antiepileptic drug characterized by several mechanisms of action, which has proved to be clinically effective in the reduction of the quantity of crisis in epileptic patients. Clinical studies frequently report subjective cognitive complains, inconsistently sustained. The main objective of this study was to assess neuropsychological effects attributable to the addition of TPM to the current antiepileptic therapy, in patients with refractory partial epilepsy.

44 patients were assessed through a cognitive battery applied before beginning of therapy with TPM and 6 months after the dosage had been stabilized. Tests had been chosen to assess verbal and non verbal memory, executive functions, language, visuomotor processing and psychomotor functions. The cognitive study was conducted in parallel with clinical trials TOPMAT-EPAJ-111 and TOP-POR1.

The statistical analysis of results didn t show changes in motor tests, in sustained attention and in logical and visual memory. Deterioration of semantic verbal fluency, verbal learning, work memory and visuomotor skills was observed. Considering the effects of the dosage of topiramate and the total quantity of antiepileptic drugs, major commitment was observed in patients taking more than 400 mg/day.

Like other antiepileptic drugs, topiramate, used in polytherapy in patients with refractory epilepsy, may have consequences on cognitive functions. These changes may be related with the potentiating action of this drug at the level of neurotransmission system of gamma amino butyric acid (GABA), substance that has inhibitory properties in the fore regions of the brain.