Stockbridge Melissa D, Matchin William, Walker Alexandra, Breining Bonnie, Fridriksson Julius, Hickok Gregory, Hillis Argye E
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21287.
Department of Communication Sciences and Disorders, University of South Carolina Arnold School of Public Health, Columbia, SC 29208.
Aphasiology. 2021;35(12):1-12. doi: 10.1080/02687038.2020.1852167. Epub 2021 Mar 16.
Progressive neurodegenerative impairment with central language features, primary progressive aphasia (PPA), can be further distinguished for many individuals into one of three variants: semantic, non-fluent/agrammatic, and logopenic variant PPA. Variants differ in their relative preservation and deficits of language skills, particularly in word finding and grammar. The majority of elicited language assessments used in this population focus on single noun and verb production, while modifiers and inflectional morphemes are far less commonly examined.
The purpose of the present study is to determine whether there was an interaction between PPA variant and production of high-frequency nouns, proper names, modifiers, and bound inflectional morphemes to better understand how the variants differ.
METHODS & PROCEDURES: Forty-six people with PPA and 47 individuals with no known neurological diagnoses completed a morphosyntactic generation assessment designed to target differential production of high-frequency nouns, proper names, modifiers (number, size, color), and bound inflectional morphemes (plural -s and possessive 's), the Morphosyntactic Generation test (MorGen). Performance is averaged for each of the seven morphosyntactic targets independently, resulting in seven separate performance scores.
OUTCOMES & RESULTS: Individuals with PPA performed significantly more poorly than controls on the assessed morphemes in a repeated-measures analysis of variance, as well as on each morpheme considered independently via t-test.In a multivariable analysis of variance among PPA variants, the interaction of morpheme and PPA variant was significant, suggesting different variants produced the morphemes with a significantly different pattern of success. When morphemes were considered independently, only production of colour resulted in a significant difference between variants, driven by the performance of individuals with nfavPPA, who performed near-ceiling. When MorGen performance was used to predict PPA variant in a multinomial logistic regression the model was significant, with age, plural -s, noun, and number contributing significantly to the prediction. In a discriminate function analysis, classification of cases was best for agrammatic variant with 70% accuracy.
Individuals with PPA, particularly semantic and logopenic variants, demonstrated difficulty on the MorGen compared to controls. The MorGen proved useful in predicting PPA variant. These findings highlight the potential benefit of examining a broader range of morphemes, particularly bound morphemes and modifiers, in addition to the more frequently investigated classes of nouns and verbs when understanding PPA.
进行性神经退行性损害伴有中枢性语言特征，即原发性进行性失语（PPA），对许多个体而言可进一步分为三种变体之一：语义性、非流畅/语法缺失性和音韵性变体PPA。这些变体在语言技能的相对保留和缺陷方面存在差异，尤其是在找词和语法方面。该人群中使用的大多数引发性语言评估聚焦于单个名词和动词的产出，而修饰语和屈折语素则较少被考察。
本研究的目的是确定PPA变体与高频名词、专有名词、修饰语和粘着屈折语素的产出之间是否存在相互作用，以更好地理解这些变体之间的差异。
46名PPA患者和47名无已知神经学诊断的个体完成了一项形态句法生成评估，旨在针对高频名词、专有名词、修饰语（数量、大小、颜色）和粘着屈折语素（复数-s和所有格's）的差异产出，即形态句法生成测试（MorGen）。对七个形态句法目标中的每一个分别计算平均表现，得出七个独立的表现分数。
在重复测量方差分析中，PPA患者在评估的语素上的表现明显比对照组差，通过t检验对每个单独考虑的语素进行分析时也是如此。在PPA变体之间的多变量方差分析中，语素与PPA变体的相互作用显著，表明不同变体产出语素的成功模式存在显著差异。当单独考虑语素时，只有颜色的产出在变体之间导致了显著差异，这是由非流畅/语法缺失性变体PPA患者的表现驱动的，他们的表现接近上限。当使用MorGen表现通过多项逻辑回归预测PPA变体时，模型具有显著性，年龄、复数-s、名词和数量对预测有显著贡献。在判别函数分析中，对语法缺失性变体的病例分类准确率最高，为70%。
与对照组相比，PPA患者，尤其是语义性和音韵性变体患者，在MorGen测试中表现出困难。MorGen被证明有助于预测PPA变体。这些发现突出了在理解PPA时，除了更常研究的名词和动词类别外，考察更广泛的语素，特别是粘着语素和修饰语的潜在益处。
