Vonk Jet M J, Borghesani Valentina, Battistella Giovanni, Younes Kyan, DeLeon Jessica, Welch Ariane, Hubbard H Isabel, Miller Zachary A, Miller Bruce L, Gorno-Tempini Maria Luisa
Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands.
Aphasiology. 2020;34(7):865-885. doi: 10.1080/02687038.2019.1659935. Epub 2019 Sep 4.
Semantic variant primary progressive aphasia (svPPA), a clinical syndrome characterized by loss of semantic knowledge, is associated with neurodegeneration that starts in the anterior temporal lobe (ATL) and gradually spreads towards posterior temporal and medial frontal areas. At the earliest stages, atrophy may be predominantly lateralized to either the left or right ATL, leading to different clinical profiles with greatest impairment of word comprehension or visual/social semantics, respectively.
METHODS & PROCEDURES: We report the in-depth longitudinal investigation of cognitive and neuroanatomical features of JB, an unusual case of ATL neurodegeneration with relative sparing of left lateral ATL regions.
OUTCOMES & RESULTS: Over the course of nine years, neurodegeneration progressed to involve bilateral temporo-lateral and frontal regions, resulting in a relatively symmetric and diffuse frontotemporal atrophy pattern. In parallel, JB developed greater behavioral, cognitive, and language impairments, as well as signs of motor neuron disease at her last evaluation. Episodic memory and socio-emotional processing deficits arose, likely secondary to semantic verbal deficits, while visuospatial processing, executive function, and non-semantic language abilities remained largely unaffected throughout the course of the disease.
The details of this rare case of early medial more than lateral ATL degeneration are consistent with a bilateral organization of the semantic system and, crucially, with a functional dissociation between medial paralimbic and lateral neocortical temporal regions. Cases of frontotemporal dementia (FTD) such as JB, who initially do not meet current clinical criteria for svPPA and instead present with some features of behavioral variant FTD, highlight the need for specific criteria for the right temporal variant of FTD that we propose could be called semantic variant FTD.
语义变异型原发性进行性失语（svPPA）是一种以语义知识丧失为特征的临床综合征，与始于颞叶前部（ATL）并逐渐向后颞叶和额内侧区域扩散的神经退行性变有关。在最早阶段，萎缩可能主要局限于左或右ATL的一侧，分别导致以单词理解或视觉/社会语义受损最严重的不同临床特征。
我们报告了对JB认知和神经解剖学特征的深入纵向研究，JB是一例不寻常的ATL神经退行性变病例，左侧外侧ATL区域相对保留。
在九年的时间里，神经退行性变进展至双侧颞外侧和额叶区域，导致相对对称且弥漫的额颞叶萎缩模式。与此同时，JB出现了更严重的行为、认知和语言障碍，以及在最后一次评估时出现运动神经元病的体征。情景记忆和社会情感加工缺陷出现，可能继发于语义言语缺陷，而视觉空间加工、执行功能和非语义语言能力在疾病过程中基本未受影响。
这例罕见的早期内侧而非外侧ATL变性病例的细节与语义系统的双侧组织一致，关键的是，与内侧边缘旁和外侧新皮质颞区之间的功能分离一致。像JB这样的额颞叶痴呆（FTD）病例，最初不符合当前svPPA的临床标准，而是表现出行为变异型FTD的一些特征，凸显了针对我们提出的可称为语义变异型FTD的FTD右颞叶变异型制定特定标准的必要性。
