Stewart Raj, Wingfield Arthur
Volen National Center for Complex Systems (MS 013), Brandeis University, Waltham, MA 02454-9110, USA.
J Am Acad Audiol. 2009 Feb;20(2):147-54. doi: 10.3766/jaaa.20.2.7.
In addition to declines in auditory acuity, adult aging is often also accompanied by reduced cognitive efficiency, most notably in working memory resources and a general slowing in a number of perceptual and cognitive domains. Effectiveness of speech comprehension by older adults reflects a balance between these declines and the relative preservation in healthy aging of linguistic knowledge and the procedural rules for its application.
To examine effects of hearing acuity in older adults on intelligibility functions for sentences that varied in two degrees of syntactic complexity, with their concomitant demands on older adults' working memory resources.
Stimuli consisted of monosyllabic words presented in isolation, and nine-word sentences that varied in syntactic complexity. Two sentence types were employed: sentences with a subject-relative clause structure, and more syntactically complex sentences in which meaning was expressed with an object-relative clause structure. The stimuli were presented initially below the level of audibility and then increased in loudness in 2 dB increments until the single-word stimuli and all nine words of the sentence stimuli could be correctly reported.
Participants were 16 older adults with good hearing acuity for their ages, 16 age-matched adults with mild-to-moderate hearing loss, and 16 young adults with age-normal hearing.
Along with confirming better report accuracy for the words of meaningful sentences than for words heard in isolation, performance curves for the sentence stimuli showed a significant effect of syntactic complexity. This took the form of older adults having poorer report accuracy at any given loudness level for sentences with greater syntactic complexity. This general effect of syntactic complexity on perceptual report accuracy was further exacerbated by age and hearing loss.
Age-limited working memory resources are impacted both by the resource demands required for comprehension of syntactically complex sentences and by effortful listening attendant to hearing loss.
除了听力敏锐度下降外，成年人衰老通常还伴随着认知效率降低，最明显的是工作记忆资源减少以及多个感知和认知领域普遍变慢。老年人言语理解的有效性反映了这些衰退与健康衰老过程中语言知识及其应用程序规则的相对保留之间的平衡。
研究老年人的听力敏锐度对两种句法复杂程度不同的句子的可理解性功能的影响，以及它们对老年人工作记忆资源的相应需求。
刺激材料包括单独呈现的单音节词和句法复杂程度不同的九个词的句子。使用了两种句子类型：具有主语关系从句结构的句子，以及句法更复杂、用宾语关系从句结构表达意义的句子。刺激材料最初以听不见的水平呈现，然后以2分贝的增量增加音量，直到能够正确报告单个词刺激材料和句子刺激材料的所有九个词。
参与者包括16名听力与其年龄相符的老年人、16名年龄匹配的轻至中度听力损失成年人以及16名听力正常的年轻人。
除了证实有意义句子中的单词报告准确率高于单独听到的单词外，句子刺激材料的表现曲线显示句法复杂性有显著影响。具体表现为，在任何给定音量水平下，句法更复杂的句子，老年人的报告准确率更低。句法复杂性对感知报告准确率的这种总体影响因年龄和听力损失而进一步加剧。
年龄受限的工作记忆资源既受到理解句法复杂句子所需的资源需求的影响，也受到听力损失导致的费力聆听的影响。
