Changes in VEP and electroretinogram under anticonvulsive therapy

Purpose: To study the effect of three new antiepileptic drugs on latency an d amplitude of the visual evoked potentials (VEP) and pattern electroretino gram (P-ERG). Methods: In 30 patients treated with lamotrigine (LTG), vigab atrin (VGB) or gabapentin (GBP) in mono- or add-on therapy, VEP and P-ERG w ere investigated. Follow-up recordings were observed in 4 patients of each group. Monocular full field pattern-reversal stimulation was used. Latency and amplitude of VEP component P100 and simultaneously recorded P-ERG-P50 w ere determined. Results: Among 13 patients with LTG treatment (25 to 600 mg /day) an abnormal VEP-P100 and P-ERG was observed in one (LTG add-on 100 mg /day) and an abnormal P-ERG in another patient (LTG monotherapy 300 mg/day) . Under VGB treatment (1 to 3 g/day)4 of 12 patients had an abnormal VEP. T he P-ERC was abnormal in 2 of these patients. Three of 7 patients with GBP (1200 to 2400 mg/day) had an abnormal P100. One of the 3 had an abnormal P- ERG additionally. Conclusions: The results confirm the effect of VGB and de monstrate the influences of LTG and in particular of GBP on VEP and P-ERG. We suppose that individual disposition to toxic effects on optic nerve tran smitter function could be responsible for these findings.