Acoustic Change Complex and Visually Reinforced Infant Speech Discrimination Measures of Vowel Contrast Detection.
Acoustic Change Complex and Visually Reinforced Infant Speech Discrimination Measures of Vowel Contrast Detection.
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DOI：
10.1097/aud.0000000000001116
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发表时间：
2022
期刊：
影响因子：
3.7
通讯作者：
Cheek Smith DE
中科院分区：
文献类型：
--
作者：
Cone BK;Smith S;Cheek Smith DE
目的是测量刺激率和元音变化方向对声学变化复合体 (ACC) 延迟和幅度的影响，并将 ACC 指标与 1 岁以下婴儿的元音对比检测行为指标进行比较。我们测试了以下假设：由于皮质神经元对频率变化方向的敏感性，元音变化引起的频谱能量移动方向会导致 ACC 差异。我们评估了刺激速率（1/s 与 2/s）对婴儿 ACC 的影响。我们评估了 ACC 振幅比的敏感性（每次变化试验中 ACC 的比例），并将其与使用视觉强化婴儿言语辨别范式 (VRISD) 获得的感知反应进行比较。该报告为 ACC 提供了婴儿的规范数据，以实现开发临床上有用的元音辨别神经能力指数的最终目标。 29 名婴儿（9 名女性，年龄 4.0-11.8 个月）参与了研究。所有参与者均足月出生并通过了新生儿听力筛查。没有人有听力或神经损伤的危险因素。皮层听觉诱发电位是根据以 1- 或 2/s 的速率呈现的合成元音标记 /a/、/i/、/o/ 和 /u/ 获得的，在奇怪的刺激范式中，异常刺激的概率为 25%。元音标记的所有组合均以两种速率进行测试。 ACC 是针对异常刺激而获得的。还使用 VRISD 范例对婴儿进行元音对比检测测试，并使用与 ACC 相同的元音标记组合。 ACC 测试时的平均年龄为 5.4 个月，而行为测试时的平均年龄为 6.8 个月。 ACC 幅度和延迟的变化是作为初始元音标记和对比标记的函数而发生的。然而，元音（频谱）变化的方向将导致高到低频谱变化的显着更大的变化响应的假设并未得到支持。以 /a/ 作为对比对的前导元音的对比导致比其他条件最大的 ACC 幅度。观察到 ACC 存在和振幅随速率变化的显着差异，其中 2/s 导致 ACC 具有最大振幅比。元音对比度和速率的延迟效应存在，但不是系统性的。 ACC 振幅比检测元音对比度的灵敏度对于 2/s 速率高于 1/s 速率。对于 ≥ 1.5 的振幅比标准，ACC 分量 P2-N2 在 2/s 时的灵敏度为 93%，而在 1/s 时灵敏度为 70%。 VRISD 元音对比检测测试的命中率为 71%，假阳性率为 21%。许多无法达到 VRISD 表现标准的婴儿的 ACC 振幅比≥ 2.0。当在 1 岁以下的典型发育婴儿中获得时，以 2/s 的速率呈现的元音对比 ACC 是元音对比检测的稳健指标。当使用 ≥1.5 的振幅比标准来定义响应时，超过 90% 的婴儿以该比率进行测试时存在 ACC。振幅比似乎是衡量对照条件和对比度条件之间差异的敏感指标。 ACC 可以在尚未对元音变化对比表现出有效行为反应的婴儿中获得，并且可能有助于估计辨别这些声音的神经能力。
The objectives were to measure the effect of stimulus rate and vowel-change direction on the acoustic change complex (ACC) latencies and amplitudes and compare ACC metrics to behavioral measures of vowel-contrast detection for infants tested under the age of 1 year. We tested the hypothesis that the direction of spectral energy shift from a vowel change would result in differences in the ACC, owing to the sensitivity of cortical neurons to the direction of frequency change. We evaluated the effect of the stimulus rate (1/s vs. 2/s) on the infants’ ACC. We evaluated the ACC amplitude ratio’s sensitivity (proportion of ACCs present for each change trial) and compared it to perceptual responses obtained using a visually-reinforced infant speech discrimination paradigm (VRISD). This report provides normative data from infants for the ACC towards the ultimate goal of developing a clinically useful index of neural capacity for vowel discrimination. Twenty-nine infants, nine females, aged 4.0–11.8 months, participated. All participants were born at full-term and passed their newborn hearing screens. None had risk factors for hearing or neurologic impairment. Cortical auditory evoked potentials were obtained in response to synthesized vowel tokens /a/, /i/, /o/ and /u/ presented at a rate of 1- or 2/s in an oddball stimulus paradigm with a 25% probability of the deviant stimulus. All combinations of vowel tokens were tested at the two rates. The ACC was obtained in response to the deviant stimulus. The infants were also tested for vowel-contrast detection using a VRISD paradigm with the same combinations of vowel tokens used for the ACC. The mean age at the time of the ACC test was 5.4 months, while the mean age at the behavioral test was 6.8 months. Variations in ACC amplitude and latency occurred as a function of the initial vowel token and the contrast token. However, the hypothesis that the direction of vowel (spectral) change would result in significantly larger change responses for high-to-low spectral changes was not supported. The contrasts with /a/ as the leading vowel of the contrast pair resulted in the largest ACC amplitudes than other conditions. Significant differences in the ACC presence and amplitude were observed as a function of rate, with 2/s resulting in ACCs with the largest amplitude ratios. Latency effects of vowel contrast and rate were present, but not systematic. The ACC amplitude ratio’s sensitivity for detecting a vowel contrast was greater for the 2/s rate than the 1/s rate. For an amplitude ratio criterion of ≥ 1.5, the sensitivity was 93% for ACC component P2-N2 at 2/s, whereas at 1/s sensitivity was 70%. VRISD tests of vowel-contrast detection had a 71% hit and a 21% false-positive rate. Many infants who could not reach performance criteria for VRISD had ACC amplitude ratios ≥ 2.0. The ACC for vowel contrasts presented at a rate of 2/s is a robust index of vowel-contrast detection when obtained in typically developing infants under the age of 1 year. The ACC is present in over 90% of infants tested at this rate when an amplitude ratio criterion of ≥1.5 is used to define a response. The amplitude ratio appears to be a sensitive metric for the difference between a control and contrast condition. The ACC can be obtained in infants who do not yet exhibit valid behavioral responses for vowel change contrasts and may be useful for estimating neural capacity for discriminating these sounds.