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

Abstract 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 64ms). 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).目的：分析噪声对不同年龄正常听力个体皮层听觉诱发电位（cortical auditory evoked potentials）的电生理测量指标（P1-N1-P2复合波）的影响。方法：本研究纳入年龄18~75岁、听阈≤25 dB的青年、成年及老年人群。按年龄分为三组：G1组（18~25岁）、G2组（31~59岁）及G3组（60~75岁）。采用合成语音刺激/da/，分别在无掩蔽与掩蔽（Delta-t 64ms）两种条件下诱发皮层听觉诱发电位，通过统计学方法对结果进行表述与分析。结果：所有年龄组在Delta-t 64ms掩蔽条件下均出现潜伏期延长与波幅降低的现象。不同年龄组间在两种条件下的P1潜伏期，以及Delta-t 64ms条件下的N1潜伏期均存在显著差异。无掩蔽条件下的P1潜伏期在G1组更低，而Delta-t 64ms条件下的P1与N1潜伏期在G3组更高。本研究结果显示，噪声对所有年龄组的皮层听觉反应均存在影响，其中G3组受掩蔽刺激的影响最为显著。结论：潜伏期与波幅测量值随刺激呈现条件及年龄组的不同而发生变化，前向掩蔽（forward masking）现象在G3组中表现出更高的精准度。证据等级：(2c)。