Department of Otolaryngology, Johns Hopkins University School of Medicine Baltimore, MD, USA.
Department of Otolaryngology - Head and Neck Surgery, Chi-Mei Medical Center, Taipei Medical University Tainan, Taiwan, China.
Front Neurosci. 2014 Sep 9;8:282. doi: 10.3389/fnins.2014.00282. eCollection 2014.
Sensitivity to complex pitch is notoriously poor in adults with cochlear implants (CIs), but it is unclear whether this is true for children with CIs. Many are implanted today at a very young age, and factors related to brain plasticity (age at implantation, duration of CI experience, and speaking a tonal language) might have strong influences on pitch sensitivity. School-aged children participated, speaking English or Mandarin, having normal hearing (NH) or wearing a CI, using their clinically assigned settings with envelope-based coding strategies. Percent correct was measured in three-interval three-alternative forced choice tasks, for the discrimination of fundamental frequency (F0) of broadband harmonic complexes, and for the discrimination of sinusoidal amplitude modulation rate (AMR) of broadband noise, with reference frequencies at 100 and 200 Hz to focus on voice pitch processing. Data were fitted using a maximum-likelihood technique. CI children displayed higher thresholds and shallower slopes than NH children in F0 discrimination, regardless of linguistic background. Thresholds and slopes were more similar between NH and CI children in AMR discrimination. Once the effect of chronological age was extracted from the variance, the aforementioned factors related to brain plasticity did not contribute significantly to the CI children's sensitivity to pitch. Unless different strategies attempt to encode fine structure information, potential benefits of plasticity may be missed.
对人工耳蜗植入者(CI)来说,复杂音高的敏感性很差,这是众所周知的,但对于植入 CI 的儿童来说,情况是否如此还不清楚。如今,许多儿童在很小的时候就被植入了 CI,而与大脑可塑性相关的因素(植入年龄、CI 体验的持续时间以及说声调语言)可能对音高敏感性有很大的影响。本研究纳入了学龄儿童,他们使用基于 envelope 的编码策略,以临床分配的设置,用英语或普通话进行交流,具有正常听力(NH)或佩戴 CI。在三间隔三选择强制反应任务中,测量了基本频率(F0)的宽带谐波复合体和宽带噪声的正弦幅度调制率(AMR)的辨别率,参考频率为 100Hz 和 200Hz,以集中于语音音高处理。使用最大似然技术拟合数据。无论语言背景如何,CI 儿童在 F0 辨别中的阈值和斜率都高于 NH 儿童。在 AMR 辨别中,NH 儿童和 CI 儿童的阈值和斜率更相似。一旦从方差中提取出年龄的影响,与大脑可塑性相关的上述因素对 CI 儿童的音高敏感性没有显著贡献。除非采用不同的策略来编码精细结构信息,否则可能会错过可塑性的潜在益处。