Effects of phenytoin and sodium valproate on cognition and mood Thai epileptic patients

Abstract

To evaluate the effects of phenytoin (PHT) and sodium valproate (VPA) as monotherapy on cognitive function of Thai epileptic patients, Stroop Color Word Test (SCWT) and Wechsler Abbreviated Scale of Intelligence (WASI®) were used to examine neuropsychological status. In addition, mood status and adverse events was evaluated by Profiles of Mood States (POMS®) and Adverse Event Profile (AEP), respectively. Eligible patients were recruited from Neurology Clinic, Pramongkutklao Hospital. They consisted of 2 groups of 15 patients in each, and received either PHT or VPA. Fifteen of age and sex matched normal volunteers were recruited by similar criteria. A Battery of tests was administered to the study population for 3 times with 1 month interval. No significant difference was noted in clinical features of the three groups of subjects except the level of education. SCWT revealed no difference in score of attention performance. Another cognitive domain that was not significantly affected by the administration of PHT and VPA is verbal knowledge reflected by Verbal Intelligence Quotients (VIQ) in WASI®. Unlike VPA, cognitive deficit seen as poorer performance on performance Intelligence Quotients (PIQ), Full Scale Intelligence Qoutients-4 (FSIQ-4), and Full Scale Intelligence Quotients-2 (FSIQ-2) than those of normal volunteers were found in PHT group. Among six dimensions of mood measured, vigor is the only dimension that PHT and VPA groups were significantly different from normal volunteers. No significant difference was found on adverse events. Based on the results obtained, it is apparent that cognitive functioning of Thai epileptic patients was adversely affected by PHT but not VPA. While attention and verbal knowledge were unaffected, significant deficit seem to involve executive function of the brain as indicated by WASI® In addition, vigor is the only domain of mood that showed discrepancy between epileptic patients and normal volunteers. Therefore, in comparison to PHT, VPA should be the drug of choice if cognitive functioning is a major concern. Further studies are needed to elaborate the results observed.