Buss Emily, Porter Heather L, Hall Joseph W, Grose John H
Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill.
Hearing and Speech Department, Children's Hospital Los Angeles, CA.
J Speech Lang Hear Res. 2017 Jan 1;60(1):172-181. doi: 10.1044/2016_JSLHR-H-16-0010.
The age at which gap detection becomes adultlike differs, depending on the stimulus characteristics. The present study evaluated whether the developmental trajectory differs as a function of stimulus frequency region or duration of the onset and offset ramps bounding the gap.
Thresholds were obtained for wideband noise (500-4500 Hz) with 4- or 40-ms raised-cosine ramps and for a 25-Hz-wide low-fluctuation narrowband noise centered on either 500 or 5000 Hz with 40-ms ramps. Stimuli were played continuously at 70 dB SPL, and the task was to indicate which of 3 intervals contained a gap. Listeners were 5.2- to 15.1-year-old children (n = 40) and adults (n = 10) with normal hearing.
Regardless of listener age, gap detection thresholds for the wideband noise tended to be lower when gaps were shaped using 4-ms rather than 40-ms ramps. Thresholds also tended to be lower for the low-fluctuation narrowband noise centered on 5000 Hz than 500 Hz. Performance reached adult levels after 11 years of age for all 4 stimuli. Maturation was not uniform across individuals, however; a subset of young children performed like adults, including some 5-year-olds.
For these stimuli, the developmental trajectory was similar regardless of narrowband noise center frequency or wideband noise onset and offset ramp duration.
根据刺激特性的不同，间隙检测达到成人水平的年龄也有所不同。本研究评估了发育轨迹是否会因刺激频率区域或界定间隙的起始和结束斜坡的持续时间而有所不同。
分别获取了具有4毫秒或40毫秒升余弦斜坡的宽带噪声（500 - 4500赫兹）以及以500赫兹或5000赫兹为中心、具有40毫秒斜坡的25赫兹宽的低波动窄带噪声的阈值。刺激以70分贝声压级持续播放，任务是指出三个间隔中的哪一个包含间隙。受试者为5.2至15.1岁的儿童（n = 40）和听力正常的成年人（n = 10）。
无论受试者年龄如何，当使用4毫秒而非40毫秒的斜坡来塑造间隙时，宽带噪声的间隙检测阈值往往更低。以5000赫兹为中心的低波动窄带噪声的阈值也往往低于以500赫兹为中心的窄带噪声。对于所有四种刺激，11岁后性能达到成人水平。然而，个体间的成熟情况并不一致；一小部分幼儿的表现与成年人相似，包括一些5岁的儿童。
对于这些刺激，无论窄带噪声中心频率或宽带噪声起始和结束斜坡持续时间如何，发育轨迹都是相似的。
