Assessment of temporal changes in cognitive effects induced by antiseizure medications in epilepsy patients.

Objective: Numerous studies have been conducted investigating the effects of antiseizure medications (ASMs) on cognitive functions, and the cognitive side effects of some ASMs have been demonstrated. However, data on whether tolerance to these side effects develops over time is insufficient. The aim of this study is to evaluate the reversibility of cognitive impairments caused by ASMs in patients, utilizing event-related potentials (ERPs) and the Montreal Cognitive Assessment (MoCA) test.

Materials and methods: The single-center prospective study was conducted from July 2022 to August 2023. This study enrolled participants aged 18 to 50 who had been diagnosed with epilepsy and were planning to commence treatment with an antiseizure medication (ASM). The inclusion criteria comprised individuals aged between 18 and 50 years, with a diagnosis of epilepsy, and who were intending to initiate a new ASM as monotherapy. Exclusion criteria encompassed individuals younger than 18 or older than 50 years, those diagnosed with psychogenic non-epileptic seizures, those currently on antiepileptic drugs, and those with cognitive dysfunction or dementia. Before starting treatment, patients were subjected to the MoCA test and ERP measurements by a neurologist. These tests and measurements were repeated at the second and sixth months of treatment.

Result: The study included a cohort of 254 participants with a mean age of 32.6 (±14) years. At the second month after starting treatment with carbamazepine (CBZ), zonisamide (ZNS), valproic acid (VPA), and topiramate (TPM), both MoCA and ERP values showed significantly worse cognitive impairment compared to before treatment (p < 0.05). This impairment showed a significant improvement by the sixth month for CBZ, ZNS, and VPA (p < 0.05). Although there was improvement in MoCA and ERP values in patients using TPM, the changes remained statistically significant compared to baseline values (p < 0.05). In patients using levetiracetam, lamotrigine, oxcarbazepine, and lacosamide, cognitive impairment was not statistically significant at either the second or sixth month.

Conclusion: This study demonstrated that the detrimental cognitive effects associated with CBZ, VPA, and ZNS could be reversible. Although some improvement was observed over time with TPM, the absence of significant recovery suggests that additional time may be required for a substantial reversal of these effects.