Moeller Mary Pat, Hoover Brenda, Putman Coille, Arbataitis Katie, Bohnenkamp Greta, Peterson Barbara, Wood Sharon, Lewis Dawna, Pittman Andrea, Stelmachowicz Pat
Boys Town National Research Hospital, Omaha, Nebraska 68131, USA.
Ear Hear. 2007 Sep;28(5):605-27. doi: 10.1097/AUD.0b013e31812564ab.
Infants with hearing loss are known to be slower to develop spoken vocabulary than peers with normal hearing. Previous research demonstrates that they differ from normal-hearing children in several aspects of prelinguistic vocal development. Less is known about the vocalizations of early-identified infants with access to current hearing technologies. This longitudinal study documents changes in prelinguistic vocalizations in early-identified infants with varying degrees of hearing loss, compared with a group of infants with normal hearing. It was hypothesized that infants with hearing loss would demonstrate phonetic delays and that selected aspects of phonetic learning may be differentially affected by restricted auditory access.
The vocalizations and early verbalizations of 21 infants with normal hearing and 12 early-identified infants with hearing loss were compared over a period of 14 mo (from 10 to 24 mo of age). Thirty-minute mother-child interaction sessions were video recorded at 6- to 8-wk intervals in a laboratory playroom setting. Syllable complexity changes and consonantal development were quantified from vocalizations and early verbalizations. Early behaviors were related to speech production measures at 36 mo of age. Participants with hearing loss were recruited from local audiology clinics and early intervention programs. Participants with normal hearing were recruited through day care centers and pediatrician offices.
Relative to age-matched, normal-hearing peers, children with hearing loss were delayed in the onset of consistent canonical babble. However, certain children with moderately-severe losses babbled on time, and infants with cochlear implants babbled within 2 to 6 mo of implantation. The infants with hearing loss had smaller consonantal inventories and were slower to increase syllable shape complexity than age-matched normal-hearing peers. The overall pattern of results suggested that consonant development in infants with hearing loss was delayed but not qualitatively different from children with normal hearing. Delays appeared to be less pronounced than suggested by previous research. However, fricative/affricate development progressed slowly in infants with hearing loss and divergence from the patterns of normal-hearing children was observed. Six children (2 with normal hearing; 4 with hearing loss) were identified as atypical, based on their rates of development. At 24 mo of age, these children persisted in producing a high proportion (0.59) of vocalizations lacking consonants, which was negatively correlated with Goldman-Fristoe scores at 36 mo (r = -0.60).
Results suggest that early-identified children are delayed in consonant and syllable structure development, which may influence early word learning rates. Fricative/affricate development appears to be challenging for some infants with hearing loss. This may be related to the effects of sensorineural hearing loss on high-frequency information, restricted bandwidth provided by amplification, and reduced audibility in contexts of noise and reverberation. Delayed fricative use may have implications for morphological development. Atypically slow rates of change in syllable development may indicate that a child is at risk for delayed speech development.
众所周知，听力损失婴儿的口语词汇发展比听力正常的同龄人要慢。先前的研究表明，他们在语言前发声发展的几个方面与听力正常的儿童不同。对于早期确诊且能使用当前听力技术的婴儿的发声情况，我们了解得较少。这项纵向研究记录了不同程度听力损失的早期确诊婴儿在语言前发声方面的变化，并与一组听力正常的婴儿进行了比较。研究假设是，听力损失婴儿会出现语音延迟，并且语音学习的某些方面可能会受到有限听觉接触的不同影响。
对21名听力正常的婴儿和12名早期确诊有听力损失的婴儿在14个月（从10个月到24个月大）的时间里的发声和早期言语进行了比较。在实验室游戏室环境中，每隔6至8周对30分钟的母婴互动环节进行视频记录。从发声和早期言语中量化音节复杂性变化和辅音发展情况。早期行为与36个月大时的言语产生指标相关。有听力损失的参与者是从当地听力诊所和早期干预项目中招募的。听力正常的参与者是通过日托中心和儿科医生办公室招募的。
与年龄匹配的听力正常同龄人相比，听力损失儿童在持续规范牙牙学语的开始时间上有所延迟。然而，某些中重度听力损失的儿童按时开始牙牙学语，接受人工耳蜗植入的婴儿在植入后2至6个月内开始牙牙学语。与年龄匹配的听力正常同龄人相比，听力损失婴儿的辅音库较小，音节形状复杂性增加得较慢。总体结果模式表明，听力损失婴儿的辅音发展有所延迟，但在质量上与听力正常的儿童没有差异。延迟似乎没有先前研究表明的那么明显。然而，听力损失婴儿的擦音/塞擦音发展进展缓慢，并且观察到与听力正常儿童的模式有所不同。根据发展速度，确定了6名儿童（2名听力正常；4名听力损失）为非典型。在24个月大时，这些儿童持续发出高比例（0.59）的无辅音发声，这与36个月时的戈德曼-弗里斯托分数呈负相关（r = -0.60）。
结果表明，早期确诊的儿童在辅音和音节结构发展方面有所延迟，这可能会影响早期单词学习速度。对于一些听力损失婴儿来说，擦音/塞擦音发展似乎具有挑战性。这可能与感音神经性听力损失对高频信息的影响、放大设备提供的有限带宽以及在噪声和混响环境中可听度降低有关。延迟使用擦音可能对形态发展有影响。音节发展中异常缓慢的变化速度可能表明儿童存在言语发展延迟的风险。
