Primary progressive aphasia patients evaluated using diffusion tensor imaging and voxel based volumetry-preliminary results

Abstract

There are individuals who have a progressive language deficit without presenting cognitive deficits in other areas. One of the diseases related to this presentation is primary progressive aphasia (PPA). Objective: Identify by means of diffusion tensor imaging (DTI) and measurements of cortical volume, brain areas that lead to dysphasia when presenting signs of impaired connectivity or reduced volume. Method: Four patients with PPA were evaluated using DTI, and measurements of cortical volumes in temporal areas. These patients were compared with two normal volunteers. Results: There is a trend to a difference in the number and volume of related fibers between control group and patients with PPA. Comparing cortical volumes in temporal areas between groups yielded a trend to a smaller volume in PPA patients. Conclusion: Patients with PPA have a trend to impairment in cortical and subcortical levels regarding relevant areas. Key words: anomia, primary progressive aphasia, DTI, tractography, arcuate fasciculus, language Avaliação de pacientes com afasia primária progressiva com imagem tensor de difusão e volumetria baseada em voxels RESUMO Existem indivíduos que apresentam deterioração progressiva da linguagem sem apresentar déficits em outros domínios cognitivos; estes pacientes em geral apresentam afasia primária progressiva (APP). Objetivo: Identificar, pela imagenologia, áreas cerebrais que quando sofrem atrofia, ou quando seu sistema de conexões apresenta alterações, levam a disfasia. Método: Foram avaliados quatro pacientes com APP, utilizando-se ressonância magnética com as técnicas de imagem por tensores da difusão (DTI) e medida do volume cortical em áreas de interesse previamente definidas. Estes pacientes foram comparados com um grupo controle constituído por dois voluntários. Resultados: Redução da média dos volumes dos giros temporais esquerdos no grupo de pacientes, em relação ao grupo controle, e alterações quanto ao volume e número de fibras nos tratos correspondentes. Conclusão: Pacientes com APP têm tendência a apresentar danos tanto ao nível cortical quanto subcortical. Palavras-chave: anomia, afasia primária progressiva, DTI, tratografia, volume cerebral, fascículo arqueado, linguagem. Correspondence Fábio Pascotto de Oliveira

Fractional Anisotropy in Three Variants of Primary Progressive Aphasia

“…However, these results confirmed the results of studies on larger groups of PPA subjects [7,8,9,10,11] and suggest that DTI could be a useful tool even at an individual level for current clinical practice in a multimodal diagnostic classification. Differentiating between PPA and Alzheimer’s disease is sometimes difficult.…”

“…Five semantic dementia and seven non-fluent aphasia patients were included in the frontotemporal dementia group [5]. However, DTI has rarely been specifically applied to PPA subtypes and is always applied across a large sample of patients [7,8,9,10,11]. …”

Networks Disrupted in Linguistic Variants of Frontotemporal Dementia

“…Additionally, a recent study showed that tracts, such as the uncinate fasciculus, the superior longitudinal fasciculus, the retrolenticular part of internal capsule, the inferior frontooccipital fasciculus, posterior thalamic radiation, and posterior corona radiata are associated with this stream (70). Similarly, other studies supported alterations in white matter in uncinate (18, 54, 56), inferior longitudinal fasciculi (55, 57, 61, 71) Patients with svPPA have impaired comprehension of content words (nouns, verbs, adjectives), anomia, and semantic impairment (4, 72).…”