Cognitive effects of topiramate revealed by standardised low-resolution brain electromagnetic tomography (sLORETA) of event-related potentials

Abstract

Objective: To evaluate the effect of topiramate (TPM) on event-related potentials (ERPs) in patients with epilepsy.

Methods: Neuropsychological tests and ERP study using auditory oddball paradigm were conducted before and after treatment with TPM in drug-naive epilepsy patients. To detect target brain regions in which ERP changed during the cognitive task, cortical current densities of ERP components were analysed using standardised low-resolution electromagnetic tomography (sLORETA).

Results: Neuropsychological tests (n=18 patients) showed that TPM significantly decreased the score in digit span, Corsi block and Controlled Oral Word Association word fluency. Repeated-measures analysis of variance of ERP data (n=13 patients) revealed that P2 amplitude was significantly increased at Fz electrode following treatment with TPM. Statistical non-parametric map of sLORETA between pre- and post-TPM ERPs revealed that current density of P200 component was significantly reduced by TPM in bilateral parieto-occipital, temporolimbic and dorsolateral right prefrontal regions.

Conclusions: Our findings suggest that TPM affects selective brain regions which may be related to cognitive side effects.

Significance: Source localisation of ERPs can be helpful in identifying target brain regions for the cognitive side effects of anti-epileptic drugs.