Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, 37007 Salamanca, Spain; Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, 37007 Salamanca, Spain.
Departamento de Psicología Experimental, Procesos Cognitivos y Logopedia, Universidad Complutense de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain.
Hear Res. 2024 Sep 15;451:109080. doi: 10.1016/j.heares.2024.109080. Epub 2024 Jul 11.
Auditory masking methods originally employed to assess behavioral frequency selectivity have evolved over the years to infer cochlear tuning. Behavioral forward masking thresholds for spectrally notched noise maskers and a fixed, low-level probe tone provide accurate estimates of cochlear tuning. Here, we use this method to investigate the effect of stimulus duration on human cochlear tuning at 500 Hz and 4 kHz. Probes were 20-ms sinusoids at 10 dB sensation level. Maskers were noises with a spectral notch symmetrically and asymmetrically placed around the probe frequency. For seven participants with normal hearing, masker levels at masking threshold were measured in forward masking for various notch widths and for masker durations of 30 and 400 ms. Measurements were fitted assuming rounded exponential filter shapes and the power spectrum model of masking, and equivalent rectangular bandwidths (ERBs) were inferred from the fits. At 4 kHz, masker thresholds were higher for the shorter maskers but ERBs were not significantly different for the two masker durations (ERB=294 Hz vs. ERB=277 Hz). At 500 Hz, by contrast, notched-noise curves were shallower for the 30-ms than the 400-ms masker, and ERBs were significantly broader for the shorter masker (ERB=126 Hz vs. ERB=55 Hz). We discuss possible factors that may underlay the duration effect at low frequencies and argue that it may not be possible to fully control for those factors. We conclude that tuning estimates are not affected by maker duration at high frequencies but should be measured and interpreted with caution at low frequencies.
听觉掩蔽方法最初用于评估行为频率选择性，多年来已发展为推断耳蜗调谐。带频谱凹口噪声掩蔽器和固定低水平探测音的行为前掩蔽阈值可准确估计耳蜗调谐。在此，我们使用该方法研究刺激持续时间对 500 Hz 和 4 kHz 人耳蜗调谐的影响。探测音为 10 dB 感觉水平的 20 ms 正弦音。掩蔽器是在探测频率周围对称和非对称放置的带频谱凹口噪声。对于 7 名听力正常的参与者，在各种凹口宽度和掩蔽器持续时间为 30 和 400 ms 的情况下，在正向掩蔽中测量掩蔽阈值下的掩蔽器水平。测量结果假设为圆形指数滤波器形状和掩蔽的功率谱模型拟合，并从拟合中推断等效矩形带宽（ERB）。在 4 kHz 时，较短的掩蔽器的掩蔽器阈值较高，但两个掩蔽器持续时间的 ERB 没有显著差异（ERB=294 Hz 与 ERB=277 Hz）。相比之下，在 500 Hz 时，对于 30 ms 的掩蔽器，带凹口噪声曲线比 400 ms 的掩蔽器更浅，较短的掩蔽器的 ERB 明显更宽（ERB=126 Hz 与 ERB=55 Hz）。我们讨论了可能导致低频下持续时间效应的因素，并认为可能无法完全控制这些因素。我们的结论是，在高频时调谐估计不受掩蔽器持续时间的影响，但在低频时应谨慎测量和解释。
