The effect of noise on the amplitude and morphology of cortical auditory evoked potentials

OBJECTIVE: To analyze the effect of noise on electrophysiological measurements (P1-N1-P2 complex) of cortical auditory evoked potentials in normal hearing individuals of different ages. METHODS: The inclusion criteria for the study were young individuals, adults and elderly, aged 18–75 years, with auditory thresholds up to 25 dB. Participants were separated according to their age group: G1 (18–25 years old), G2 (31–59 years old) and G3 (60–75 years old). Cortical auditory evoked potentials were elicited with synthetic speech stimulus /da/ presented in two conditions: without masking and with masking (Delta-t 64 ms). The results were expressed and analyzed using statistical measures. RESULTS: High latencies and reduced amplitudes were observed in the Delta-t 64 ms condition, in all age groups. There were significant differences between the groups, both in P1 latencies for the two conditions and in N1 latencies in the Delta-t 64 ms condition. P1 latencies in the condition without masking were lower in G1 and P1 and N1 latencies in the Delta-t 64 ms condition were higher in G3. The described results show the influence of noise on cortical responses in all age groups, with G3 being the most affected by the masking presentation. CONCLUSION: The latency and amplitude measurements vary according to the stimulus presentation condition and age group. The forward masking phenomenon occurred with greater precision in G3. LEVEL OF EVIDENCE: (2c).