Duong Anh, Whitehead Victor, Hanratty Kate, Chertkow Howard
Bloomfield Center for Research in Aging, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, McGill University, Canada.
Neuropsychologia. 2006;44(10):1928-35. doi: 10.1016/j.neuropsychologia.2006.01.034. Epub 2006 Apr 17.
Lexico-semantic impairments in Alzheimer disease (AD) have been attributed to abnormalities in both intentional and automatic access to semantic memory. However, the order in which these impairments appear during the course of the disease is unclear. We sought to answer this question by documenting lexico-semantic impairments in 61 subjects with mild cognitive impairment (MCI), a pre-AD stage, and by comparing them to those of 39 AD and 60 normal elderly (NE) subjects. All subjects were tested with intentional access tasks (picture naming and semantic probes), automatic access tasks (lexical decision and priming), and executive function tasks (Stroop and Stroop-Picture naming). Results indicated that the MCI group was only impaired on tasks of intentional access relative to the AD group who was impaired on both types of tasks. Because most MCI subjects eventually develop AD, these results suggest that intentional access to semantic memory is impaired before automatic access. Further, impairments on the Stroop-Picture naming task but not on the Stroop task, suggest that lexico-semantic impairments in the MCI group may be related to inhibition deficits during semantic search. Findings are discussed in light of executive dysfunctions within the framework of semantic memory theories.
阿尔茨海默病（AD）中的词汇语义损伤被归因于语义记忆的有意和自动提取过程中的异常。然而，这些损伤在疾病过程中出现的顺序尚不清楚。我们试图通过记录61名处于AD前期即轻度认知障碍（MCI）阶段的受试者的词汇语义损伤，并将其与39名AD患者和60名正常老年人（NE）的损伤进行比较，来回答这个问题。所有受试者都接受了有意提取任务（图片命名和语义探测）、自动提取任务（词汇判断和启动）以及执行功能任务（斯特鲁普和斯特鲁普图片命名）的测试。结果表明，相对于在两种类型任务中均受损的AD组，MCI组仅在有意提取任务上受损。由于大多数MCI受试者最终会发展为AD，这些结果表明语义记忆的有意提取在自动提取之前就已受损。此外，斯特鲁普图片命名任务而非斯特鲁普任务上的损伤表明，MCI组的词汇语义损伤可能与语义搜索过程中的抑制缺陷有关。我们将根据语义记忆理论框架内的执行功能障碍来讨论这些发现。
