Validating new diagnostic imaging criteria for primary progressive aphasia via anatomical likelihood estimation meta‐analyses

Abstract

Recently, diagnostic clinical and imaging criteria for primary progressive aphasia (PPA) have been revised by an international consortium (Gorno-Tempini et al. Neurology 2011;76:1006-14). The aim of this study was to validate the specificity of the new imaging criteria and investigate whether different imaging modalities [magnetic resonance imaging (MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET)] require different diagnostic subtype-specific imaging criteria. Anatomical likelihood estimation meta-analyses were conducted for PPA subtypes across a large cohort of 396 patients: firstly, across MRI studies for each of the three PPA subtypes followed by conjunction and subtraction analyses to investigate the specificity, and, secondly, by comparing results across MRI vs. FDG-PET studies in semantic dementia and progressive nonfluent aphasia. Semantic dementia showed atrophy in temporal, fusiform, parahippocampal gyri, hippocampus, and amygdala, progressive nonfluent aphasia in left putamen, insula, middle/superior temporal, precentral, and frontal gyri, logopenic progressive aphasia in middle/superior temporal, supramarginal, and dorsal posterior cingulate gyri. Results of the disease-specific meta-analyses across MRI studies were disjunct. Similarly, atrophic and hypometabolic brain networks were regionally dissociated in both semantic dementia and progressive nonfluent aphasia. In conclusion, meta-analyses support the specificity of new diagnostic imaging criteria for PPA and suggest that they should be specified for each imaging modality separately.

Disentangling the neural correlates of corticobasal syndrome and corticobasal degeneration with systematic and quantitative ALE meta-analyses

“…pre-central gyrusL. superior frontal sulcus and middle frontal gyrusParkinson’s syndromes Parkinson’s disease 15, 16 −−−++ Atypical Parkinson’s syndromes   CBD and syndromePresent meta-analysis++ (posterior)+++   Progressive supranuclear palsy 15 +−−+−   Multiple system atrophy 16 +−−−−   Lewy body dementia 40* (−)(−)(−)(−)(−)Alzheimer’s disease 9, 12, 41 +−−−−Behavioral variant frontotemporal dementia 8–11 −+ (anterior)−−−Primary progressive aphasias Nonfluent/ agrammatic variant (progressive non-fluent aphasia) 9, 10, 42 −−−−+ Semantic variant (semantic dementia) 9, 10, 42, 43 −−−−− Logopenic variant (logopenic aphasia) 42 −−−−−Meta-analyses were conducted by calculating ALEs in the gray matter. Other methods, such as effect-size signed differential mapping, were not taken into account to avoid a bias of different methods.…”

Characterisation of “Positive” Behaviours in Primary Progressive Aphasias

“…Three PPA phenotypes are generally recognised: a nonfluent/agrammatic variant (nfvPPA; also known as progressive nonfluent aphasia) that is characterised by agrammatism in language production and effortful speech; a semantic variant (svPPA; also known as semantic dementia) that is characterised by anomia and single-word comprehension deficits; and a logopenic variant (lvPPA; also known as logopenic progressive aphasia) that is characterised by word retrieval and sentence repetition deficits [2]. The classification of these phenotypes is based on the type and severity of language deficit and the pattern of brain atrophy observed on neuroimaging scans [3,4]. Additionally, each PPA subtype is associated with a specific and predominant abnormal deposition of protein in the brain: tau (>70%) in nfvPPA, TDP-43 (>90%) in svPPA, and Alzheimer disease pathology in lvPPA [5].…”

Caracterización del lenguaje en las variantes lingüísticas de la Afasia Progresiva Primaria

“…Sin embargo, si el diagnóstico se realiza en un estadio muy avanzado de la enfermedad, los pacientes probablemente encajarán predominantemente en la categoría de 'APP mixta'. Además, la línea divisoria entre las categorías agramática y logopénica es difusa, tanto por dificultades en la evaluación de la gramática, que es difícil de cuantificar (Mesulam et al, 2014;Bisenius, Neumann & Schroeter, 2016) como en los hallazgos de las pruebas de neuroimagen (Bisenius et al, 2016). Los criterios propuestos por Mesulam et al (2014) que definen a la gramática y la comprensión como dimensiones nucleares en el diagnóstico diferencial de los subtipos de APP, así como la necesidad de considerar un subtipo mixto, son respaldados por el estudio de Vandenberghe (2016).…”