Faria Andreia V, Sebastian Rajani, Newhart Melissa, Mori Susumu, Hillis Argye E
Department of Radiology, Johns Hopkins University, Baltimore, MD 21205, USA.
Department of Neurology, Johns Hopkins University School of Medicine, 600 N. Wolfe Street, Baltimore MD 21287, USA.
Aphasiology. 2014 Aug;28(8-9):948-963. doi: 10.1080/02687038.2014.911241.
Three variants of primary progressive aphasia (PPA), distinguished by language performance and supportive patterns of atrophy on imaging, have different clinical courses and the prognoses for specific functions. For example, semantic variant PPA alone is distinguished by impaired word comprehension. However, sometimes individuals with high education show normal performance on word comprehension tests early on, making classification difficult. Furthermore, as the condition progresses, individuals with other variants develop word comprehension deficits and other behavioral symptoms, making distinctions between variants less clear. Longitudinal brain imaging allows identification of specific areas of atrophy in individual patients, which identifies the location of disease in each patient.
We hypothesized that the areas of atrophy in individual PPA participants would be closely correlated with decline in word comprehension over time. We propose that areas where tissue volume is correlated with word comprehension are areas that: (1) are essential for word comprehension, (2) compensate for word comprehension in some individuals with semantic variant PPA early in the course; and (3) show atrophy in individuals with logopenic and nonfluent variant PPA only late in the course.
Fifteen participants with PPA (5 logopenic variant PPA; 8 semantic variant PPA; 2 nonfluent/agrammatic variant PPA; mean age 67.8), underwent high resolution MRI and cognitive tests at least 9 months apart. The correlations between change in regional volumes and change in auditory word comprehension scores were investigated using Spearman test.
OUTCOMES & RESULTS: While scores on auditory word comprehension at Time 1 were correlated with volume loss in right and left temporal pole and left inferior temporal cortex (areas of atrophy associated with semantic variant PPA), deterioration in auditory word comprehension from Time 1 to Time 2 was associated with individual atrophy in left middle temporal cortex, left angular gyrus, and right inferior and middle temporal cortex.
Progressive atrophy in focal areas surrounding left temporal pole and left inferior temporal cortex, and right homologous area is closely related to progressive decline in auditory word comprehension. These correlations likely reflect areas that help support auditory word comprehension, effectively compensating for subtle deficits in some individuals early in the course of semantic variant PPA, as well as areas that are critical for auditory word comprehension that eventually atrophy in individuals with other variants of PPA. Individual patterns of atrophy also help us understand and predict the clinical course of individuals, such as associated behavioral or motor deficits.
原发性进行性失语（PPA）有三种变体，根据语言表现和影像学上支持性的萎缩模式来区分，它们具有不同的临床病程和特定功能的预后情况。例如，语义变体PPA的独特之处在于词汇理解受损。然而，有时受过高等教育的个体在早期的词汇理解测试中表现正常，这使得分类变得困难。此外，随着病情进展，其他变体的个体也会出现词汇理解缺陷和其他行为症状，使得变体之间的区别变得不那么明显。纵向脑成像能够识别个体患者萎缩的特定区域，从而确定每位患者疾病的位置。
我们假设个体PPA参与者的萎缩区域会随着时间的推移与词汇理解能力的下降密切相关。我们提出，组织体积与词汇理解相关的区域是那些：（1）对词汇理解至关重要的区域；（2）在语义变体PPA病程早期对一些个体的词汇理解起到补偿作用的区域；（3）仅在病程后期在音韵性失语和非流利性变体PPA个体中出现萎缩的区域。
15名PPA参与者（5名音韵性失语变体PPA；8名语义变体PPA；2名非流利/语法缺失变体PPA；平均年龄67.8岁），相隔至少9个月接受了高分辨率MRI和认知测试。使用Spearman检验研究区域体积变化与听觉词汇理解分数变化之间的相关性。
虽然第一次测试时的听觉词汇理解分数与左右颞极和左颞下回皮质（与语义变体PPA相关的萎缩区域）的体积减少相关，但从第一次测试到第二次测试期间听觉词汇理解能力的恶化与左颞中皮质、左角回以及右颞下和颞中皮质的个体萎缩相关。
左颞极和左颞下回皮质周围以及右侧同源区域的进行性萎缩与听觉词汇理解能力的进行性下降密切相关。这些相关性可能反映了有助于支持听觉词汇理解的区域，在语义变体PPA病程早期有效地补偿了一些个体的细微缺陷，以及对听觉词汇理解至关重要但最终在其他PPA变体个体中出现萎缩的区域。个体萎缩模式也有助于我们理解和预测个体的临床病程，如相关的行为或运动缺陷。
