Integrated Program in Neuroscience, McGill University, Montreal, QC, Canada; Center for Research on Brain, Language, and Music, McGill University, Montreal, QC, Canada.
Center for Research on Brain, Language, and Music, McGill University, Montreal, QC, Canada; School of Communication Sciences and Disorders, McGill University, Montreal, QC, Canada; Haskins Laboratories, New Haven, CT, United States.
Neuropsychologia. 2018 Aug;117:261-270. doi: 10.1016/j.neuropsychologia.2018.06.009. Epub 2018 Jun 12.
It is well known that congenitally blind adults have enhanced auditory processing for some tasks. For instance, they show supra-normal capacity to perceive accelerated speech. However, only a few studies have investigated basic auditory processing in this population. In this study, we investigated if pitch processing enhancement in the blind is a domain-general or domain-specific phenomenon, and if pitch processing shares the same properties as in the sighted regarding how scores from different domains are associated. Fifteen congenitally blind adults and fifteen sighted adults participated in the study. We first created a set of personalized native and non-native vowel stimuli using an identification and rating task. Then, an adaptive discrimination paradigm was used to determine the frequency difference limen for pitch direction identification of speech (native and non-native vowels) and non-speech stimuli (musical instruments and pure tones). The results show that the blind participants had better discrimination thresholds than controls for native vowels, music stimuli, and pure tones. Whereas within the blind group, the discrimination thresholds were smaller for musical stimuli than speech stimuli, replicating previous findings in sighted participants, we did not find this effect in the current control group. Further analyses indicate that older sighted participants show higher thresholds for instrument sounds compared to speech sounds. This effect of age was not found in the blind group. Moreover, the scores across domains were not associated to the same extent in the blind as they were in the sighted. In conclusion, in addition to providing further evidence of compensatory auditory mechanisms in early blind individuals, our results point to differences in how auditory processing is modulated in this population.
众所周知，先天性失明的成年人在某些任务中具有增强的听觉处理能力。例如，他们表现出超常的感知加速语音的能力。然而，只有少数研究调查了该人群的基本听觉处理。在这项研究中，我们调查了盲人的音高处理增强是一种领域普遍现象还是领域特定现象，以及音高处理是否与视力正常者具有相同的特性，即不同领域的分数如何相关。15 名先天性失明的成年人和 15 名视力正常的成年人参加了这项研究。我们首先使用识别和评分任务创建了一组个性化的母语和非母语元音刺激。然后，使用自适应辨别范式确定言语（母语和非母语元音）和非言语（乐器和纯音）的音高方向辨别频率差限。结果表明，与对照组相比，盲人参与者对母语元音、音乐刺激和纯音的辨别阈值更好。而在盲人组中，对音乐刺激的辨别阈值小于言语刺激，这与之前在视力正常者中发现的结果一致，但我们在当前的对照组中没有发现这种效应。进一步的分析表明，年龄较大的视力正常参与者对乐器声音的阈值比对言语声音的阈值高。这种年龄效应在盲人组中没有发现。此外，各领域的分数在盲人之间的相关性不如在视力正常者之间那么强。总之，除了为早期失明个体的补偿性听觉机制提供进一步的证据外，我们的结果还表明，该人群的听觉处理方式存在差异。
