Ozmeral Erol J, Eddins Ann C, Eddins David A
Department of Communication Sciences & Disorders, University of South Florida, Tampa.
J Speech Lang Hear Res. 2018 Sep 19;61(9):2376-2385. doi: 10.1044/2018_JSLHR-H-18-0056.
The goal was to evaluate the potential effects of increasing hearing loss and advancing age on spectral envelope perception.
Spectral modulation detection was measured as a function of spectral modulation frequency from 0.5 to 8.0 cycles/octave. The spectral modulation task involved discrimination of a noise carrier (3 octaves wide from 400 to 3200 Hz) with a flat spectral envelope from a noise having a sinusoidal spectral envelope across a logarithmic audio frequency scale. Spectral modulation transfer functions (SMTFs; modulation threshold vs. modulation frequency) were computed and compared 4 listener groups: young normal hearing, older normal hearing, older with mild hearing loss, and older with moderate hearing loss. Estimates of the internal spectral contrast were obtained by computing excitation patterns.
SMTFs for young listeners with normal hearing were bandpass with a minimum modulation detection threshold at 2 cycles/octave, and older listeners with normal hearing were remarkably similar to those of the young listeners. SMTFs for older listeners with mild and moderate hearing loss had a low-pass rather than a bandpass shape. Excitation patterns revealed that limited spectral resolution dictated modulation detection thresholds at high but not low spectral modulation frequencies. Even when factoring out (presumed) differences in frequency resolution among groups, the spectral envelope perception was worse for the group with moderate hearing loss than the other 3 groups.
The spectral envelope perception as measured by spectral modulation detection thresholds is compromised by hearing loss at higher spectral modulation frequencies, consistent with predictions of reduced spectral resolution known to accompany sensorineural hearing loss. Spectral envelope perception is not negatively impacted by advancing age at any spectral modulation frequency between 0.5 and 8.0 cycles/octave.
本研究旨在评估听力损失加重和年龄增长对频谱包络感知的潜在影响。
测量频谱调制检测作为频谱调制频率（从0.5至8.0周期/倍频程）的函数。频谱调制任务涉及在对数音频频率范围内，区分具有平坦频谱包络的噪声载波（400至3200 Hz，宽3个倍频程）与具有正弦频谱包络的噪声。计算并比较了4组听众的频谱调制传递函数（SMTF；调制阈值与调制频率）：年轻正常听力者、老年正常听力者、轻度听力损失的老年人和中度听力损失的老年人。通过计算兴奋模式获得内部频谱对比度的估计值。
听力正常的年轻听众的SMTF呈带通型，在2周期/倍频程处调制检测阈值最低，听力正常的老年听众与年轻听众的SMTF非常相似。轻度和中度听力损失的老年听众的SMTF呈低通而非带通形状。兴奋模式显示，有限的频谱分辨率决定了高频而非低频频谱调制频率下的调制检测阈值。即使排除各组间（假定的）频率分辨率差异，中度听力损失组的频谱包络感知仍比其他3组差。
通过频谱调制检测阈值测量的频谱包络感知在较高频谱调制频率下会因听力损失而受损，这与已知的伴随感音神经性听力损失的频谱分辨率降低的预测一致。在0.5至8.0周期/倍频程之间的任何频谱调制频率下，频谱包络感知都不会受到年龄增长的负面影响。
