Visual evoked responses were recorded in response to a series of consonants and non-linguistic signs randomly presented. We compared, with a sample of 16 young volunteers, P300 and N400 latency and amplitude in order to detect possible asymmetries. Results in amplitude showed a significant asymmetry within right hemisphere, both in P300 and N400 components. Latency results failed to present any significant difference during the discrimination of consonants, while non-linguistic signs discrimination reflect an asymmetrical tendency in P300 component.