Holt Colleen M, Demuth Katherine, Yuen Ivan
1Audiology and Speech Pathology, The University of Melbourne, Melbourne, Victoria, Australia; and 2ARC Centre of Excellence in Cognition and its Disorders, Centre for Language Sciences and Department of Linguistics, Macquarie University, Sydney, New South Wales, Australia.
Ear Hear. 2016 Jul-Aug;37(4):e256-62. doi: 10.1097/AUD.0000000000000253.
The purpose of this study is to assess the use of prosodic and contextual cues to focus by prelingually deaf adolescent users of cochlear implants (CIs) when identifying target phonemes. We predict that CI users will have slower reaction times to target phonemes compared with a group of normally-hearing (NH) peers. We also predict that reaction times will be faster when both prosodic and contextual (semantic) cues are provided.
Eight prelingually deaf adolescent users of CIs and 8 adolescents with NH completed 2 phoneme-monitoring experiments. Participants were aged between 13 and 18 years. The mean age at implantation for the CI group was 1.8 years (SD: 1.0). In the prosodic condition, reaction times to a target phoneme in a linguistically focused (i.e., stressed) word were compared between the two groups. The semantic condition compared reaction time with target phonemes when contextual cues to focus were provided in addition to prosodic cues.
Reaction times of the CI group were slower than those of the NH group in both the prosodic and semantic conditions. A linear mixed model was used to compare reaction times using Group as a fixed factor and Phoneme and Subject as random factors. When only prosodic cues (prosodic condition) to focus location were provided, the mean reaction time of the CI group was 512 msec compared with 317 msec for the NH group, and this difference was significant (p < 0.001). The provision of contextual cues speeded reaction times for both groups (semantic condition), indicating that top-down processing aided both groups in their search for a focused item. However, even with both prosodic and contextual cues, the CI users' processing times remained slower, compared with the NH group, with mean reaction times of 385 msec for the CI users but 232 msec for the NH listeners (p < 0.001).
Prelingually deaf CI users' processing of prosodic cues is less efficient than that of their NH peers, as evidenced by slower reaction times to targets in phoneme monitoring. The provision of contextual cues speeded reaction times for both NH and CI groups, although the CI users were slower in responding than the NH group. These findings contribute to our understanding of how CI users employ/integrate prosodic and semantic cues in speech processing.
本研究旨在评估人工耳蜗（CI）植入的语前聋青少年使用者在识别目标音素时对韵律和语境线索的利用情况。我们预测，与一组听力正常（NH）的同龄人相比，CI使用者对目标音素的反应时间会更长。我们还预测，当同时提供韵律和语境（语义）线索时，反应时间会更快。
8名语前聋的CI植入青少年使用者和8名听力正常的青少年完成了两项音素监测实验。参与者年龄在13至18岁之间。CI组的平均植入年龄为1.8岁（标准差：1.0）。在韵律条件下，比较了两组对语言聚焦（即重读）单词中目标音素的反应时间。语义条件下，除了韵律线索外，还提供聚焦的语境线索时，比较了对目标音素的反应时间。
在韵律和语义条件下，CI组的反应时间均比NH组慢。使用线性混合模型，以组为固定因素，音素和受试者为随机因素比较反应时间。当仅提供聚焦位置的韵律线索（韵律条件）时，CI组的平均反应时间为512毫秒，而NH组为317毫秒，差异显著（p < 0.001）。提供语境线索加快了两组的反应时间（语义条件），表明自上而下的加工有助于两组寻找聚焦项。然而，即使同时有韵律和语境线索，与NH组相比，CI使用者的加工时间仍然较慢，CI使用者的平均反应时间为385毫秒，而NH组听众为232毫秒（p < 0.001）。
语前聋的CI使用者对韵律线索的加工效率低于听力正常的同龄人，音素监测中对目标的反应时间更长证明了这一点。提供语境线索加快了NH组和CI组的反应时间，尽管CI使用者的反应比NH组慢。这些发现有助于我们理解CI使用者在语音加工中如何运用/整合韵律和语义线索。
