Werner L A, Mancl L R, Folsom R C
University of Washington, Department of Speech and Hearing Sciences, Seattle, USA.
Ear Hear. 1996 Dec;17(6):455-68. doi: 10.1097/00003446-199612000-00002.
Hearing loss commonly is associated with Down syndrome, but little is known about the development of auditory sensitivity in individuals with Down syndrome. This study had two objectives: 1) to determine whether an observer-based procedure can be used to assess the behavioral sensitivity of infants with Down syndrome, and 2) to provide preliminary information about the early course of hearing development among infants with Down syndrome.
Behavioral measures of sensitivity were made in 16 infants with Down syndrome using an observer-based procedure. Ten of the infants were followed longitudinally between 2 and 12 mo of age. All infants passed a screening auditory brain stem response at 20 dB nHL during the study and completed screening tympanometry at each test session. The infants detected a 4000 Hz tone at levels ranging from 25 to 50 dB SPL; psychometric functions and thresholds for the tone were obtained.
Infants with Down syndrome completed 80% of the test sessions they began, a rate similar to that seen in normally developing infants in the same type of study. Performance improved with increasing stimulus level, as one would expect, and thresholds were obtained from 15 of 16 infants for at least one age. The performance of infants with Down syndrome generally improved with age. The sensitivity of 2- to 3-mo-olds was poorer than that of older infants, but little if any improvement in sensitivity occurred between 4 and 12 mo. This pattern is similar to that seen in normally developing infants. Thresholds of infants with Down syndrome were 10 to 25 dB higher than those reported for normally developing infants. The psychometric functions of infants with Down syndrome were shallower than the psychometric functions of normally developing infants, and the slope of the psychometric functions did not change with age. Infants with Down syndrome achieved only 75 to 80% correct at any of the levels tested, 5 to 10% poorer than reported for other infants. These characteristics of the psychometric functions of the infants with Down syndrome suggest that they are inattentive during testing more often than are normally developing infants.
An observer-based procedure can be used to obtain reasonable thresholds from infants with Down syndrome who are as young as 2 mo of age. Both sensory and nonsensory factors could contribute to the threshold elevation seen in infants with Down syndrome. At least on preliminary examination, the course of auditory sensitivity development of infants with Down syndrome is qualitatively similar to that seen in normally developing infants.
听力损失通常与唐氏综合征相关，但对于唐氏综合征个体听觉敏感性的发展了解甚少。本研究有两个目的：1）确定基于观察者的程序是否可用于评估唐氏综合征婴儿的行为敏感性，以及2）提供有关唐氏综合征婴儿听力发展早期过程的初步信息。
使用基于观察者的程序对16名唐氏综合征婴儿进行敏感性的行为测量。其中10名婴儿在2至12月龄期间进行纵向跟踪。在研究期间，所有婴儿在20 dB nHL时通过了听觉脑干反应筛查，并在每次测试时完成了鼓室图筛查。婴儿能在25至50 dB SPL的水平检测到4000 Hz的纯音；获得了该纯音的心理测量函数和阈值。
唐氏综合征婴儿完成了他们开始的80%的测试环节，这一比率与同类型研究中正常发育婴儿的比率相似。正如预期的那样，随着刺激水平的增加，表现有所改善，16名婴儿中有15名在至少一个年龄段获得了阈值。唐氏综合征婴儿的表现通常随着年龄增长而改善。2至3月龄婴儿的敏感性比大龄婴儿差，但在4至12月龄之间敏感性几乎没有改善。这种模式与正常发育婴儿相似。唐氏综合征婴儿的阈值比正常发育婴儿报告的阈值高10至25 dB。唐氏综合征婴儿的心理测量函数比正常发育婴儿的心理测量函数更平缓，并且心理测量函数的斜率不随年龄变化。唐氏综合征婴儿在任何测试水平下的正确率仅为75%至80%，比其他婴儿报告的结果差5%至10%。唐氏综合征婴儿心理测量函数的这些特征表明，与正常发育婴儿相比，他们在测试期间更常注意力不集中。
基于观察者的程序可用于从低至2月龄的唐氏综合征婴儿中获得合理的阈值。感觉和非感觉因素都可能导致唐氏综合征婴儿出现阈值升高。至少在初步检查中，唐氏综合征婴儿听觉敏感性发展过程在质量上与正常发育婴儿相似。
