Electroacoustic and electrophysiological auditory assessment in aphasic individuals

ABSTRACT Purpose: to verify the functioning of the outer hair cells and the medial efferent olivocochlear system, and the integrity of the auditory pathways in the brainstem up to the auditory cortex, in aphasic individuals. Methods: the sample comprised 20 individuals - 10 without aphasia and 10 with it, aged from 21 to 58 years. The procedures used were the research of the otoacoustic emissions by a transient stimulus with and without noise, and the cognitive potential (tone-burst and speech stimuli). The findings were analyzed based on descriptive statistics. Results: the suppression effect was more present in individuals without aphasia when compared with the aphasic ones. In the cognitive potential, the mean latency values of P3 was within normality standards, with a higher latency in the individuals presented with aphasia for the tone-burst stimulus in both ears. A statistically significant difference of the P3-N2 amplitude was observed for the tone-burst stimulus, comparing the ears in both groups, and for speech stimulus only to the left ear in both groups. Conclusions: aphasic individuals did not present significant differences regarding suppression of the otoacoustic emissions. As for the cognitive potential, the aphasic individuals presented higher latency values when compared to those with no aphasia.摘要 研究目的：旨在验证失语症（aphasia）患者的外毛细胞、内侧橄榄耳蜗传出系统（medial efferent olivocochlear system）功能，以及脑干直至听觉皮层的听觉通路完整性。 研究方法：本研究纳入20名受试者，其中非失语症患者与失语症患者各10名，年龄范围为21至58岁。采用的检测手段包括：带噪声与不带噪声的瞬态刺激诱发性耳声发射（otoacoustic emissions）检测，以及认知电位（cognitive potential）检测（含短声刺激（tone-burst）与言语刺激）。检测结果采用描述性统计学方法进行分析。 研究结果：与失语症患者相比，非失语症受试者的耳声发射抑制效应更为显著。在认知电位检测中，P3波的平均潜伏期符合正常参考标准；但针对双耳的短声刺激，失语症患者的潜伏期均更高。两组受试者在短声刺激下的双耳P3-N2振幅差异均具有统计学意义；而言语刺激下，仅两组的左耳间存在统计学显著差异。 研究结论：失语症患者在耳声发射抑制效应方面未出现显著差异。而就认知电位而言，失语症患者的潜伏期较非失语症患者更高。