Apeksha Kumari, Kumar U Ajith
Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysore, 570006, India.
Eur Arch Otorhinolaryngol. 2018 Jun;275(6):1409-1418. doi: 10.1007/s00405-018-4966-8. Epub 2018 Apr 9.
Auditory neuropathy spectrum disorder (ANSD) is a condition where cochlear amplification function (involving outer hair cells) is normal but neural conduction in the auditory pathway is disordered. This study was done to investigate the cortical representation of speech in individuals with ANSD and to compare it with the individuals with normal hearing.
Forty-five participants including 21 individuals with ANSD and 24 individuals with normal hearing were considered for the study. Individuals with ANSD had hearing thresholds ranging from normal hearing to moderate hearing loss. Auditory cortical evoked potentials-through odd ball paradigm-were recorded using 64 electrodes placed on the scalp for /ba/-/da/ stimulus. Onset cortical responses were also recorded in repetitive paradigm using /da/ stimuli. Sensitivity and reaction time required to identify the oddball stimuli were also obtained.
Behavioural results indicated that individuals in ANSD group had significantly lower sensitivity and longer reaction times compared to individuals with normal hearing sensitivity. Reliable P300 could be elicited in both the groups. However, a significant difference in scalp topographies was observed between the two groups in both repetitive and oddball paradigms. Source localization using local auto regressive analyses revealed that activations were more diffuses in individuals with ANSD when compared to individuals with normal hearing sensitivity.
Results indicated that the brain networks and regions activated in individuals with ANSD during detection and discrimination of speech sounds are different from normal hearing individuals. In general, normal hearing individuals showed more focused activations while in individuals with ANSD activations were diffused.
听觉神经病谱系障碍（ANSD）是一种耳蜗放大功能（涉及外毛细胞）正常但听觉通路神经传导紊乱的病症。本研究旨在调查ANSD患者言语的皮层表征，并将其与听力正常的个体进行比较。
该研究纳入了45名参与者，其中包括21名ANSD患者和24名听力正常的个体。ANSD患者的听力阈值范围从正常听力到中度听力损失。使用放置在头皮上的64个电极，通过奇偶数范式记录听觉皮层诱发电位，刺激音为/ba/-/da/。还使用/da/刺激，通过重复范式记录起始皮层反应。同时获取识别奇偶数刺激所需的敏感性和反应时间。
行为学结果表明，与听力正常的个体相比，ANSD组个体的敏感性显著降低，反应时间更长。两组均能引出可靠的P300。然而，在重复范式和奇偶数范式中，两组在头皮地形图上均观察到显著差异。使用局部自回归分析进行源定位显示，与听力正常的个体相比，ANSD患者的激活更分散。
结果表明，ANSD患者在语音检测和辨别过程中激活的脑网络和区域与听力正常的个体不同。总体而言，听力正常的个体表现出更集中的激活区域，而ANSD患者的激活区域则较为分散。
