Center for the Study of Language and Information, Stanford University, Stanford, California, United States of America.
PLoS One. 2012;7(2):e30374. doi: 10.1371/journal.pone.0030374. Epub 2012 Feb 8.
Congenital amusia is a neuro-developmental disorder of pitch perception that causes severe problems with music processing but only subtle difficulties in speech processing. This study investigated speech processing in a group of Mandarin speakers with congenital amusia. Thirteen Mandarin amusics and thirteen matched controls participated in a set of tone and intonation perception tasks and two pitch threshold tasks. Compared with controls, amusics showed impaired performance on word discrimination in natural speech and their gliding tone analogs. They also performed worse than controls on discriminating gliding tone sequences derived from statements and questions, and showed elevated thresholds for pitch change detection and pitch direction discrimination. However, they performed as well as controls on word identification, and on statement-question identification and discrimination in natural speech. Overall, tasks that involved multiple acoustic cues to communicative meaning were not impacted by amusia. Only when the tasks relied mainly on pitch sensitivity did amusics show impaired performance compared to controls. These findings help explain why amusia only affects speech processing in subtle ways. Further studies on a larger sample of Mandarin amusics and on amusics of other language backgrounds are needed to consolidate these results.
先天性失歌症是一种音高知觉的神经发育障碍，它导致严重的音乐处理问题，但只有轻微的言语处理困难。本研究调查了一组患有先天性失歌症的普通话使用者的言语处理能力。13 名普通话失歌症患者和 13 名匹配的对照组参加了一系列声调感知和语调感知任务以及两个音高阈值任务。与对照组相比，失歌症患者在自然语言中的辨音和滑音类似物的辨别能力受损。他们在辨别来自陈述和问题的滑音序列以及在音高变化检测和音高方向辨别方面的表现也比对照组差。然而，他们在单词识别、自然语言中的陈述-问题识别和辨别方面的表现与对照组一样。总体而言，涉及到多种声音线索的交际意义的任务不受失歌症的影响。只有当任务主要依赖于音高敏感性时，失歌症患者的表现才会比对照组差。这些发现有助于解释为什么失歌症只以微妙的方式影响言语处理。需要对更大的普通话失歌症样本和其他语言背景的失歌症进行进一步研究，以巩固这些结果。
