Nebes R D, Brady C B
Department of Psychiatry, University of Pittsburgh.
Cortex. 1991 Jun;27(2):237-46. doi: 10.1016/s0010-9452(13)80128-1.
Subjects (Alzheimer patients, normal young and elderly individuals) heard a sentence the last word of which was missing. A visual word then appeared and the subjects decided whether it made a sensible ending to the sentence. Sentences varied in the degree to which their semantic context constrained possible endings to the sentence. The degree of contextual constraint greatly influenced response time--the greater the constraint, the faster subjects made their decisions. While Alzheimer patients were slower than normals, their decision time was affected by contextual constraint to the same degree as that of normals. Thus, the performance of Alzheimer patients was sensitive to the amount of semantic context present in sentences, and this context facilitated their ability to make conscious semantic judgements. These findings suggest that Alzheimer patients are capable of using semantic information in a task requiring attention-dependent processes.
研究对象（阿尔茨海默病患者、正常年轻人和老年人）听一个句子，句子的最后一个单词缺失。然后出现一个视觉单词，研究对象要判断这个单词是否能合理地结束这个句子。句子的语义语境对句子可能的结尾的限制程度各不相同。语境限制的程度极大地影响了反应时间——限制越大，研究对象做出决定的速度就越快。虽然阿尔茨海默病患者比正常人反应慢，但他们的决策时间受语境限制的程度与正常人相同。因此，阿尔茨海默病患者的表现对句子中语义语境的量很敏感，这种语境促进了他们做出有意识语义判断的能力。这些发现表明，阿尔茨海默病患者在一项需要注意力依赖过程的任务中能够使用语义信息。
