ABSTRACT

The logopenic variant of primary progressive aphasia (lvPPA) is characterized mainly by anomia, production of phonological errors, and impairment in repetition of sentences. The functional origin of these language impairments is mainly attributed to the breakdown of phonological short-term memory. The present study examined the effects of phonological short-term memory impairment on language processing in lvPPA. In two studies, 11 participants with lvPPA and 11 healthy control participants were presented with repetition tasks in which the type and length of stimuli and the mode of administration were manipulated. Study 1 aimed to examine the influence of length and lexicality (words vs. pseudowords) on immediate and delayed repetition, whereas Study 2 aimed to examine the influence of length, syntactic complexity (nominalized vs. pronominalized sentences), and serial position on immediate sentence repetition. Study 1 showed that participants’ performance with lvPPA was impaired only on immediate repetition of five-syllable pseudowords and on delayed repetition of words and pseudowords. Study 2 showed that participants’ performance with lvPPA was impaired in the repetition of nominalized sentences where a recency effect was observed. Repetition of pronominalized sentences was also impaired in the lvPPA group. This study provides additional support for arguments regarding phonological short-term memory as a cause of language impairment in lvPPA. Clinically, the results of the study suggest that instruments for assessing repetition ability in lvPPA should include not only lists of short or long nominalized sentences, but also delayed repetition of words and pseudowords and pronominalized sentences.

摘要

原发性进行性失语症 (lvPPA) 的语言减少变异型的主要特征是失语、语音错误和句子重复障碍。这些语言障碍的功能根源主要归因于语音短期记忆的破坏。本研究探讨了语音短期记忆障碍对 lvPPA 语言处理的影响。在两项研究中，11 名 lvPPA 参与者和 11 名健康对照参与者接受了重复任务，其中刺激的类型和长度以及给药模式受到控制。研究 1 旨在检验长度和词汇性（单词与伪词）对立即重复和延迟重复的影响，而研究 2 旨在检验长度、句法复杂性（名词化句子与代词化句子）和序列位置对立即句子的影响重复。研究1表明，参与者的lvPPA表现仅在立即重复五音节伪词以及延迟重复单词和伪词时受到损害。研究 2 表明，参与者在 lvPPA 中的表现在重复名词化句子时受到损害，其中观察到了近因效应。lvPPA 组中代词化句子的重复也受到损害。这项研究为有关语音短期记忆作为 lvPPA 语言障碍原因的论点提供了额外的支持。临床上，研究结果表明，评估lvPPA重复能力的工具不仅应包括短或长名词化句子列表，还应包括单词和伪词以及代词化句子的延迟重复。