Mackersie Carol L
School of Speech, Language, and Hearing Sciences, San Diego State University, 5500 Companile Drive, MC-1518, San Diego, CA 92182-1518, USA.
J Speech Lang Hear Res. 2007 Jun;50(3):554-63. doi: 10.1044/1092-4388(2007/038).
The purposes were (a) to compare masking of consonant bursts by adjacent vowels for listeners with and without hearing loss and (b) to determine the extent to which the temporal intraspeech masking can be reduced by a simulated hearing-aid frequency-response shaping.
Fourteen adults with sensorineural hearing loss and 10 with normal hearing participated. Seven of the participants with hearing loss had flat or gradually sloping audiograms, and 7 had steeply sloping losses. Stimuli consisted of 3 consonant bursts (/t/, /p/, /k/) presented in isolation and in vowel-consonant-vowel combinations using the vowel /a/ with formant transition information removed. Normal-hearing listeners were tested using unfiltered stimuli. Listeners with hearing loss were tested using unfiltered stimuli and stimuli filtered to approximate a hearing aid frequency response prescribed by NAL-R. All listeners were tested under earphones at the most comfortable level for the vowel stimulus. Temporal intraspeech masking was quantified as the threshold shift produced by the adjacent vowels.
Average intraspeech masking for listeners with steeply sloping hearing loss was significantly higher than that of normal-hearing listeners and those with flat/gradually sloping losses. Greater intraspeech masking was observed for /t/ and /p/ than for /k/. On average, frequency shaping significantly reduced the amount of intraspeech masking for listeners with steeply sloping hearing losses. Even with appropriate amplification/spectral shaping, however, temporal intraspeech masking remained greater than normal for several individuals.
Findings suggest that some individuals with steeply sloping losses may need additional signal processing to supplement frequency shaping to overcome the effect of temporal intraspeech masking.
本研究旨在（a）比较有听力损失和无听力损失的听众中相邻元音对辅音爆发音的掩蔽情况，以及（b）确定通过模拟助听器频率响应整形可以在多大程度上降低言语内时间掩蔽。
14名感音神经性听力损失的成年人和10名听力正常的成年人参与了研究。7名听力损失的参与者听力图为平坦或逐渐下降型，7名听力损失的参与者听力图为陡峭下降型。刺激包括3个单独呈现的和以元音-辅音-元音组合呈现的辅音爆发音（/t/、/p/、/k/），使用的元音为/a/，并去除了共振峰过渡信息。听力正常的听众使用未滤波的刺激进行测试。听力损失的听众使用未滤波的刺激和滤波后的刺激进行测试，滤波后的刺激近似于NAL-R规定的助听器频率响应。所有听众均通过耳机在元音刺激最舒适的水平下进行测试。言语内时间掩蔽通过相邻元音产生的阈值变化进行量化。
听力图为陡峭下降型听力损失的听众的平均言语内掩蔽显著高于听力正常的听众和听力图为平坦/逐渐下降型的听众。观察到/t/和/p/的言语内掩蔽比/k/更大。平均而言，频率整形显著降低了听力图为陡峭下降型听力损失的听众的言语内掩蔽量。然而，即使进行了适当的放大/频谱整形，仍有几名个体的言语内时间掩蔽仍高于正常水平。
研究结果表明，一些听力图为陡峭下降型听力损失的个体可能需要额外的信号处理来补充频率整形，以克服言语内时间掩蔽的影响。
