Pattern-reversal VEP and cortical SEP latency prolongations in epilepsy.

Twenty ambulatory outpatients with generalized tonic-clonic seizures with primary generalized discharges and photoconvulsive response on electroencephalogram (EEG) and 11 ambulatory outpatients with partial complex seizures with or without secondary generalization were studied with pattern-reversal light-emitting diode (LED) stimulator visual evoked potential (VEPs) and short-latency median nerve cortical somatosensory evoked potentials (SEPs). The patients with primary generalized epilepsy had significantly prolonged latencies of VEP components P2 and N3 and SEP component P22. The patients with partial epilepsy had significantly prolonged latency of VEP component N3. It is concluded that both functional and structural factors may cause a slowing of central impulse conduction.