Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, Illinois, USA.
Med-El Corporation, Durham, North Carolina, USA.
Ear Hear. 2021 July/Aug;42(4):1084-1096. doi: 10.1097/AUD.0000000000000979.
The objectives of the study were to (1) evaluate the impact of hearing loss on children's ability to benefit from F0 differences between target/masker speech in the context of aided speech-in-speech recognition and (2) to determine whether compromised F0 discrimination associated with hearing loss predicts F0 benefit in individual children. We hypothesized that children wearing appropriately fitted amplification would benefit from F0 differences, but they would not show the same magnitude of benefit as children with normal hearing. Reduced audibility and poor suprathreshold encoding that degrades frequency discrimination were expected to impair children's ability to segregate talkers based on F0.
Listeners were 9 to 17 year olds with bilateral, symmetrical, sensorineural hearing loss ranging in degree from mild to severe. A four-alternative, forced-choice procedure was used to estimate thresholds for disyllabic word recognition in a 60-dB-SPL two-talker masker. The same male talker produced target and masker speech. Target words had either the same mean F0 as the masker or were digitally shifted higher than the masker by three, six, or nine semitones. The F0 benefit was defined as the difference in thresholds between the shifted-F0 conditions and the unshifted-F0 condition. Thresholds for discriminating F0 were also measured, using a three-alternative, three-interval forced choice procedure, to determine whether compromised sensitivity to F0 differences due to hearing loss would predict children's ability to benefit from F0. Testing was performed in the sound field, and all children wore their personal hearing aids at user settings.
Children with hearing loss benefited from an F0 difference of nine semitones between target words and masker speech, with older children generally benefitting more than younger children. Some children benefitted from an F0 difference of six semitones, but this was not consistent across listeners. Thresholds for discriminating F0 improved with increasing age and predicted F0 benefit in the nine-semitone condition. An exploratory analysis indicated that F0 benefit was not significantly correlated with the four-frequency pure-tone average (0.5, 1, 2, and 4 kHz), aided audibility, or consistency of daily hearing aid use, although there was a trend for an association with the low-frequency pure-tone average (0.25 and 0.5 kHz). Comparisons of the present data to our previous study of children with normal hearing demonstrated that children with hearing loss benefitted less than children with normal hearing for the F0 differences tested.
The results demonstrate that children with mild-to-severe hearing loss who wear hearing aids benefit from relatively large F0 differences between target and masker speech during aided speech-in-speech recognition. The size of the benefit increases with increasing age, consistent with previously reported age effects for children with normal hearing. However, hearing loss reduces children's ability to capitalize on F0 differences between talkers. Audibility alone does not appear to be responsible for this effect; aided audibility and degree of loss were not primary predictors of performance. The ability to benefit from F0 differences may be limited by immature central processing or aspects of peripheral encoding that are not characterized in standard clinical assessments.
本研究的目的是：(1)评估听力损失对儿童在有/无言语干扰情况下，从目标/掩蔽语音中受益于基频(F0)差异的能力的影响；(2)确定与听力损失相关的 F0 辨别力受损是否可以预测个体儿童的 F0 获益。我们假设，佩戴适当放大设备的儿童将受益于 F0 差异，但他们不会像听力正常的儿童那样受益于同样的程度。预计听力下降和阈下编码不佳导致频率辨别力受损，会损害儿童根据 F0 对说话人进行分离的能力。
参与者为 9 至 17 岁的双侧、对称、感音神经性听力损失患者，听力损失程度从轻度到重度不等。使用四选一、强制选择程序来估计在 60dB SPL 双说话人掩蔽下双音节词识别的阈值。同一位男性说话者产生目标语和掩蔽语。目标词的 F0 均值与掩蔽语相同，或数字上比掩蔽语高 3、6 或 9 个半音。F0 收益定义为移位 F0 条件与未移位 F0 条件之间的阈值差异。还使用三选一、三间隔强制选择程序测量 F0 辨别阈值，以确定听力损失导致的 F0 差异敏感性降低是否可以预测儿童受益于 F0。在声场中进行测试，所有儿童均以用户设置佩戴个人助听器。
听力损失儿童受益于目标词与掩蔽语音之间 9 个半音的 F0 差异，年龄较大的儿童通常比年龄较小的儿童受益更多。一些儿童受益于 6 个半音的 F0 差异，但这并不是所有听众都一致的。F0 辨别阈值随年龄的增长而提高，并预测 9 个半音条件下的 F0 收益。一项探索性分析表明，F0 收益与四个频率纯音平均值（0.5、1、2 和 4 kHz）、助听可听度或日常助听器使用的一致性之间没有显著相关性，尽管与低频纯音平均值（0.25 和 0.5 kHz）有一定的相关性。将本研究的数据与我们之前对听力正常儿童的研究进行比较表明，与听力正常儿童相比，听力损失儿童对测试的 F0 差异的受益较小。
结果表明，佩戴助听器的轻度至重度听力损失儿童在有/无言语干扰情况下的言语识别中受益于目标和掩蔽语音之间较大的 F0 差异。随着年龄的增长，收益会增加，这与听力正常儿童的先前报告的年龄效应一致。然而，听力损失会降低儿童利用说话人之间 F0 差异的能力。可听度本身似乎并不是造成这种影响的原因；助听可听度和听力损失程度并不是表现的主要预测因素。受益于 F0 差异的能力可能受到不成熟的中枢处理或未在标准临床评估中描述的外周编码方面的限制。
