DEVELOPMENT AND PLASTICITY IN NORMAL AND IMPAIRED EARS

该项目的长期目标是了解正常儿童和特定临床儿童群体的听觉发展。一个主要的研究领域是中耳炎对听觉发育的影响。该领域的具体目标是评估有中耳炎病史的儿童在特定条件下对言语处理有特殊损害的假设：当双耳提示可用于掩蔽释放时，以及当任务设计得难以在感知上将言语与掩蔽干扰分开时。第二个主要研究领域评估被诊断为特殊语言障碍的儿童的听觉处理缺陷的性质。一个具体的目标是评估这样的假设，即这些听众在编码信号的时间方面有明确的缺陷。与之竞争的假设将被评估，即这些儿童在基于相对微妙/困难的线索的听觉处理方面有更普遍的缺陷。一个相关的目标将是控制特定语言障碍儿童的听力损失史可能产生的影响。第三个主要研究领域将研究双耳掩蔽释放的发育和基本机制。对成年听者的基础实验将解决双耳掩蔽释放是否取决于有利于检测的选择性时间加权的问题。这一领域的一项相关发展研究将调查儿童对窄带噪声掩蔽物的最大阈值降低的发现，尽管他们的最大阈值与成人对相对宽带掩蔽物的最大阈值相似。我们将检验一个假设，即儿童没有利用窄带掩模谷时代包含最佳信噪比。在所有的研究领域，大多数心理物理或语音识别方法将使用三选项或四选项的强制选择测试，并通过耳机播放声音。项目的所有阶段都将包括年龄匹配的对照听众。数据将使用方差分析和相关程序进行分析。

The long-term aim of this project is an understanding of auditory development in normal children and in specific clinical popultions of children. One major Study Area is the effect of otitis media on auditory development. The specific aim in this area is assessment of the hypothesis that children with a history of otitis media have particular impairment for the processing of speech under particular conditions: when binaural cues are available for masking release, and when the task is designed such that it is difficult to perceptually segregate the speech from masking interference. The second major Study Area assesses the nature of auditory processing deficiencies in children diagnosed with specific language impairment. One specific aim will be to evaluate the hypothesis that such listeners have explicit deficits in coding the temporal aspect of the signal. The competing hypothesis will be assessed that such children have a more general deficit in auditory processing based upon relatively subtle/difficult cues. A related aim will be to control for possible effects of hearing loss history among the children with specific language disorder. The third major Study Area will investigate developmental and basic mechanisms of binaural masking release. Basic experiments on adult listeners will address the question of whether binaural masking release depends upon selective temporal weighting of temporal epochs that are favorable for detection. A related developmental study in this area will investigate the finding that children have reduced MLDs for narrowband noise maskers even though their MLDs are adult- like for relatively wideband maskers. We will examine the hypothesis that children do not take advantage of the narrowband masker valley epochs containing the best signal-to-noise ratios. In all Study Areas, most psychophysical or speech recognition methods will use three-alternative or four- alternative forced-choice testing with sound presentation over earphones. All phases of the project will include age-matched control listeners. Data will be analyzed using analysis of variance and correlation procedures.