Comparisons of frequency selectivity in simultaneous and forward masking for subjects with unilateral cochlear impairments.
Comparisons of frequency selectivity in simultaneous and forward masking for subjects with unilateral cochlear impairments.
复制标题
单侧耳蜗损伤受试者的同步掩蔽和前向掩蔽的频率选择性比较。
DOI：
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发表时间：
1986
影响因子：
2.4
通讯作者：
B. Glasberg
中科院分区：
文献类型：
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作者：
B. Moore;B. Glasberg
描述了两个实验，其中频率选择性估计，在同时和前向掩蔽，为每只耳朵的科目中度（25-60分贝HL）单侧耳蜗听力损失。在这两个实验中，信号水平是固定的一个给定的耳朵和类型的掩蔽（同时或向前），和掩蔽水平的变化，以确定阈值，使用自适应，两个替代的强制选择程序。在实验I中，掩蔽是一种噪声，其频谱陷波以信号频率（1.0或1.5 kHz）为中心;阈值被确定为陷波宽度的函数。选择信号水平，使得在阈值处对于零陷波宽度所需的噪声水平对于每个受试者的正常耳和受损耳在同时掩蔽和前掩蔽中是相似的。与阈值有关的功能缺口宽度有一个陡峭的斜率为正常的耳朵比受损的耳朵的每一个主题。对于正常的耳朵，这些功能是陡峭的前掩蔽比同时掩蔽。这种差异被解释为抑制所致。对于受损的耳朵，在相同的方向上观察到显着差异的五个科目中的三个，但差异较小。在实验II中，心理物理调谐曲线（PTC）的存在下，确定了一个固定的陷波噪声集中在信号频率（1.0 kHz）。对于正常耳，前掩蔽比同时掩蔽更尖锐的PTC。对于受损的耳朵，PTCs是相似的同时和前掩蔽，但那些在前掩蔽往往是尖锐的掩蔽频率远离信号频率。总体而言，结果表明，抑制减少，但在中度耳蜗听力损失的情况下并不是完全没有。
Two experiments are described in which frequency selectivity was estimated, in simultaneous and forward masking, for each ear of subjects with moderate (25-60 dB HL) unilateral cochlear hearing losses. In both experiments, the signal level was fixed for a given ear and type of masking (simultaneous or forward), and the masker level was varied to determine threshold, using an adaptive, two-alternative forced-choice procedure. In experiment I, the masker was a noise with a spectral notch centered at the signal frequency (either 1.0 or 1.5 kHz); threshold was determined as a function of notch width. Signal levels were chosen so that the noise level required at threshold for a notch width of zero was similar for the normal and impaired ear of each subject in both simultaneous and forward masking. The function relating threshold to notch width had a steeper slope for the normal ear than for the impaired ear of each subject. For the normal ears, these functions were steeper in forward masking than in simultaneous masking. This difference was interpreted as resulting from suppression. For the impaired ears, significant differences in the same direction were observed for three of the five subjects, but the differences were smaller. In experiment II, psychophysical tuning curves (PTCs) were determined in the presence of a fixed notched noise centered at the signal frequency (1.0 kHz). For the normal ears, the PTCs were sharper in forward masking than in simultaneous masking. For the impaired ears, the PTCs were similar in simultaneous and forward masking, but those in forward masking tended to be sharper at masker frequencies far removed from the signal frequency. Overall, the results suggest that suppression is reduced, but not completely absent in cases of moderate cochlear hearing loss.