Leyton Cristian E, Hodges John R, McLean Catriona A, Kril Jillian J, Piguet Olivier, Ballard Kirrie J
Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW, Australia; Neuroscience Research Australia, Randwick, NSW, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia.
Neuroscience Research Australia, Randwick, NSW, Australia; ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia; School of Medical Sciences, The University of New South Wales, Sydney, NSW, Australia.
Cortex. 2015 Jun;67:122-33. doi: 10.1016/j.cortex.2015.03.011. Epub 2015 Apr 1.
Logopenic progressive aphasia is one of the clinical presentations of primary progressive aphasia and formally defined by the co-occurrence of impaired naming and sentence repetition. Impaired naming is attributed to failure of lexical retrieval, which is a multi-staged process subserved by anatomically segregated brain regions. By dissecting the neurocognitive processes involved in impaired naming, we aimed to disentangle the clinical and neuroanatomical heterogeneity of this syndrome. Twenty-one individuals (66.7% females, age range 53-83 years) who fulfilled diagnostic criteria for logopenic variant and had at least two clinical and language assessments, 1 year apart, were recruited and matched for age, sex distribution and level of education with a healthy control sample (n = 18). All participants underwent a structural brain scan at the first visit and surface-wise statistical analysis using Freesurfer. Seventeen participants with logopenic variant underwent amyloid imaging, with 14 demonstrating high amyloid retention. Based on their performance on single-word comprehension, repetition and confrontation naming, three subgroups of logopenic cases with distinctive linguistic profiles and distribution of atrophy were identified. The first subgroup (n = 10) demonstrated pure anomia and left-sided atrophy in the posterior inferior parietal lobule and lateral temporal cortex. The second subgroup (n = 6), presented additional mild deficits in single-word comprehension, and also exhibited bilateral thinning of the fusiform gyri. The third subgroup (n = 5) showed additional impaired single-word repetition, and cortical thinning focused on the left superior temporal gyrus. The subgroups differed in the proportion of cases with high amyloid retention and in the rate of decline of naming performance over time, suggesting that neurodegeneration spreads differentially throughout regions subserving word processing. In line with previous reports, these results confirm the extensive damage to the language network and, in part, explain the clinical heterogeneity observed across logopenic cases.
语义性进行性失语是原发性进行性失语的临床表现之一，其正式定义为命名障碍和句子复述障碍同时出现。命名障碍归因于词汇检索失败，这是一个由解剖学上分离的脑区支持的多阶段过程。通过剖析命名障碍所涉及的神经认知过程，我们旨在厘清该综合征的临床和神经解剖学异质性。招募了21名符合语义性变异型诊断标准且至少接受过两次间隔1年的临床和语言评估的个体（66.7%为女性，年龄范围53 - 83岁），并将其与健康对照样本（n = 18）在年龄、性别分布和教育水平上进行匹配。所有参与者在首次就诊时均接受了脑部结构扫描，并使用Freesurfer进行表面统计分析。17名语义性变异型参与者接受了淀粉样蛋白成像，其中14名显示出高淀粉样蛋白潴留。根据他们在单词理解、复述和对答命名方面的表现，确定了具有独特语言特征和萎缩分布的三个语义性病例亚组。第一亚组（n = 10）表现为单纯性命名障碍，后下顶叶小叶和颞叶外侧皮质左侧萎缩。第二亚组（n = 6）在单词理解方面还存在额外的轻度缺陷，并且梭状回也出现双侧变薄。第三亚组（n = 5）表现出额外的单词复述障碍，皮质变薄集中在左侧颞上回。这些亚组在高淀粉样蛋白潴留病例的比例以及命名表现随时间下降的速率方面存在差异，这表明神经退行性变在支持单词处理的区域中以不同方式扩散。与先前的报告一致，这些结果证实了语言网络的广泛损伤，并部分解释了在语义性病例中观察到的临床异质性。
