类别响度标度的可靠性及其与阈值的关系。
Reliability of categorical loudness scaling and its relation to threshold.
机构信息
Department of Special Education and Communication Disorders, University of Nebraska, Lincoln, Nebraska, USA.
出版信息
Ear Hear. 2010 Aug;31(4):567-78. doi: 10.1097/AUD.0b013e3181da4d15.
OBJECTIVE
To further examine the reliability of categorical loudness scaling (CLS) for individual loudness categories and for the slope of the CLS functions. And, to evaluate the relationship between CLS and audiometric threshold.
DESIGN
CLS functions were obtained in 74 subjects, 58 with hearing loss and 16 with normal hearing. CLS functions were measured at three frequencies (1, 2, and 4 kHz) in two separate sessions separated by as little as 1 wk and as much as 6 mo. Reliability of mean and median levels within each loudness category was assessed using SDs and correlation coefficients. Lines were fit to the CLS functions, and slopes of the lines were used to assess reliability and the relation between CLS and audiometric threshold.
RESULTS
Similar reliability for CLS measurements was observed in both normal-hearing and hearing-impaired subjects at all frequencies. Across both groups of subjects, correlations describing the reliability of mean stimulus level within category exceeded 0.92 at all frequencies. In addition, SDs of the mean stimulus-level difference between visits ranged from 6.6 to 7.8 dB, depending on frequency. The correlation between the slope of a straight line fitted to the entire CLS function and audiometric threshold collapsed across frequencies was 0.72. Two line segments were then fit to the CLS function: one segment was fit to the soft portion of the CLS function (categorical units < or =20) and the other segment to the loud portion (categorical unit >20). Slopes of the line fit to the entire CLS function and of the line fit to the soft portion of the CLS function were both reliable across sessions. The slope of the line fit to the soft portion increased as audiometric threshold increased, with the correlations greater than 0.86 at all frequencies. No relationship was observed between slope of the line fit to the loud portion of the CLS function and audiometric threshold. Iso-loudness contours were constructed from the CLS data and used to determine the gain that would be needed to produce "normal" loudness percepts for hearing-impaired individuals.
CONCLUSIONS
Within-subject CLS measurements were reliable across sessions both for individual loudness categories and for slope of the CLS functions. In addition, the slope of the low-level portion of the CLS function varied in a predictable manner with audiometric threshold, with slope increasing as audiometric threshold increased. Finally, gain as a function of input level needed to provide loudness percepts for individuals with hearing loss equal to the loudness percepts of normal-hearing individuals can be estimated from audiometric threshold. This finding supports the assumption that audiometric threshold and response growth (loudness) are both determined by the same underlying cochlear mechanisms.
目的
进一步检验类别响度标度（CLS）在个体响度级和 CLS 函数斜率方面的可靠性。并评估 CLS 与听阈之间的关系。
设计
在 74 名受试者中获得 CLS 函数，58 名受试者有听力损失，16 名受试者听力正常。在两个单独的会话中，在 1 周至 6 个月的时间间隔内，在 3 个频率（1、2 和 4 kHz）处测量 CLS 函数。使用标准差和相关系数评估每个响度级内平均和中位数水平的可靠性。拟合 CLS 函数的线，并使用线的斜率来评估可靠性和 CLS 与听阈之间的关系。
结果
在所有频率下，正常听力和听力受损受试者的 CLS 测量均具有相似的可靠性。在两组受试者中，描述类别内平均刺激水平可靠性的相关系数均超过 0.92。此外，两次就诊之间平均刺激水平差异的标准差在 6.6 至 7.8 dB 之间，具体取决于频率。在频率范围内，拟合整个 CLS 函数的直线斜率与听阈之间的相关性为 0.72。然后拟合 CLS 函数的两段线：一段拟合 CLS 函数的软部分（类别单位≤20），另一段拟合大声部分（类别单位>20）。整个 CLS 函数拟合线和软部分拟合线的斜率在各次会话中均可靠。拟合整个 CLS 函数的线的斜率和拟合 CLS 函数软部分的线的斜率都随听阈的增加而增加，在所有频率下相关性均大于 0.86。在 CLS 函数大声部分拟合线的斜率与听阈之间未观察到关系。从 CLS 数据构建等响曲线，并用于确定为听力受损个体产生“正常”响度感知所需的增益。
结论
个体响度级和 CLS 函数斜率的个体内 CLS 测量在各次会话中均可靠。此外，CLS 函数的低水平部分的斜率与听阈呈可预测的变化，斜率随听阈的增加而增加。最后，根据听力损失个体的响度感知所需的输入水平的增益可以从听阈中估计出来，听力损失个体的响度感知与正常听力个体的响度感知相等。这一发现支持了这样一种假设，即听阈和响应增长（响度）都由相同的耳蜗机制决定。
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