title: 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.
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Bisenius
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.|Leipzig University Medical Center, IFB Adiposity Diseases, Leipzig, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Neumann
authors.affiliation: Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.|Clinic of Cognitive Neurology, University of Leipzig, Leipzig, Germany.|Leipzig Research Center for Civilization Diseases, University of Leipzig, Leipzig, Germany.|FTLD Consortium Germany, Leipzig, Germany.
authors.forename: M L
authors.initials: ML
authors.lastname: Schroeter
mesh_terms: D018888:Aphasia, Primary Progressive / Q000000981:diagnostic imaging*; D057180:Frontotemporal Dementia / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D016013:Likelihood Functions; D008279:Magnetic Resonance Imaging / Q000592:standards*; D049268:Positron-Emission Tomography / Q000592:standards*; D017410:Practice Guidelines as Topic / Q000592:standards*; D057178:Primary Progressive Nonfluent Aphasia / Q000000981:diagnostic imaging*
keywords: logopenic progressive aphasia; meta-analysis; primary progressive aphasia; progressive nonfluent aphasia; semantic dementia