Stimulus presentation strategies for eliciting the acoustic change complex: increasing efficiency.
Stimulus presentation strategies for eliciting the acoustic change complex: increasing efficiency.
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DOI：
10.1097/aud.0b013e3181ce6355
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发表时间：
2010-06
期刊：
影响因子：
3.7
通讯作者：
Leach-Berth T
中科院分区：
文献类型：
--
作者：
Martin BA;Boothroyd A;Ali D;Leach-Berth T
目的是比较四种策略的刺激呈现在他们的效率时，产生一个语音诱发的皮质声学变化复杂（ACC）在成人和儿童。使用两秒的发作间隔中断呈现包含从/u/到/i/的单个变化的一秒刺激。使用一秒的发作间隔中断相同刺激的呈现。中断呈现1.5秒刺激，包含从/u/到/i/的变化，随后是从/i/到/u/的反向变化，使用两秒的发作间隔。使用一秒的重复间隔在/u/和/i/之间交替的刺激的连续呈现。10名听力正常的成年人（年龄22至31岁）和9名听力正常的儿童（年龄6至9岁）作为参与者。ACC是使用75 dB SPL合成元音引起的，该合成元音包含第二共振峰频率的1000 Hz变化，在/u/和/i/之间产生感知元音的变化。使用四种刺激格式从Cz记录ACC： ACC幅值表示为跨越ACC的窗口内电压波形的标准差，噪声幅值由同一窗口内每个采样点的方差估计。效率表示为ACC与噪声幅度比除以测试时间。ACC幅度没有显着不同的两个方向的第二共振峰的变化。将发作间隔从两秒减少到一秒，效率提高了近两倍。将来自两个变化方向的数据结合起来，进一步提高了效率，提高的系数接近于2的平方根。连续交替刺激呈现比中断刺激呈现更有效地诱发ACC. The的好处，消除沉默期，并在一个给定的时间段内提出的声学变化的数量增加一倍，并没有严重抵消均方根响应幅度的减少，至少在年轻的成年人和6岁的儿童。
The purpose was to compare four strategies for stimulus presentation in terms of their efficiency when generating a speech-evoked cortical acoustic change complex (ACC) in adults and children. interrupted presentation of a one-second stimulus containing a single change from /u/ to /i/ using a two-second inter-onset interval. interrupted presentation of the same stimulus using a one-second inter-onset interval. interrupted presentation of a 1.5-second stimulus containing a change from /u/ to /i/ followed by a reverse change from /i/ to /u/, using a two-second inter-onset interval. continuous presentation of a stimulus alternating between /u/ and /i/ using a one-second repetition interval. Ten normally hearing adults (ages 22 to 31 years) and nine normally hearing children (ages six to nine years) served as participants. The ACC was elicited using a 75 dB SPL synthetic vowel containing 1000 Hz changes of second formant frequency, creating a change of perceived vowel between /u/ and /i/. The ACC was recorded from Cz using four stimulus formats: ACC magnitude was expressed as the standard devation of the voltage waveform within a window believed to span the ACC. Noise magnitude was estimated from the variances at each sampling point in the same window. Efficiency was expressed in terms of the ACC-to-noise magnitude ratio divided by testing time. ACC magnitude was not significantly different for the two directions of second formant change. Reducing inter-onset interval from two seconds to one second increased efficiency by a factor close to two. Combining data from the two directions of change increased efficiency further, by a factor approximating the square root of two. Continuous alternating stimulus presentation is more efficient than interrupted stimulus presentation in eliciting the ACC. The benefits of eliminating silent periods and doubling the number of acoustic changes presented in a given time period, are not seriously offset by a reduction in rms response amplitude, at least in young adults and in children as young as 6 years old.