The Effect Of Anti-Epileptic Drugs On Visual Evoked Potential In Patients With Generalized Tonic-Clonic Seizures: A Prospective Case-Controlled Study

Objective: The main purpose of the present study was to determine whether anti-epileptic drugs induce any abnormal changes in the visual evoked potential (VEP) patterns. Methods and material: This prospective case controlled study was done at the Neurology Department of King Abdulaziz University Hospital, Jeddah, Saudi Arabia (between January 2013 and December 2014). The study subjects were divided into cases and controls; with the case group subjects being those epilepsy patients receiving antiepileptic drugs. Using the Visual Evoked Potentials (VEPs), control and case subjects were compared with respect to the values of: Latency N75, Latency P100 and Amplitude P100. Results: A statistically significant difference was seen between the controls and the subjects receiving antiepileptic double and triple drug therapy; with respect to the value of Latency P100 (P-value 0.042 and 0.044 respectively). The analysis of variances (ANOVA) revealed a statistically significant difference (P-value 0.007 and 0.038) with respect to the mean scores of Latency N75 and the mean scores of Amplitude P100; in relation to age; between the controls and the case group patients receiving anti-epileptic monotherapy. A statistically significant difference (p=0.01) was noted with respect to Latency N75 related to age, between the controls and patients receiving antiepileptic double therapy. A significant difference was also noted in Latency P100 mean scores related to age (p=0.05). A gender-wise comparison revealed a statistically significant difference, in the mean scores of Latency P100, with the difference showing a male predilection Conclusion: Anti-epileptic drugs can induce abnormalities in the VEP patterns. Age and gender are factors that can influence the occurrence of such abnormalities; in relation to the number of anti-epileptic drugs taken by the patients. Future studies are recommended to evaluate the impact of the type and duration of epilepsy, in causing VEP related abnormalities