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

Eur J Neurol. 2016 Apr;23(4):704-12. doi: 10.1111/ene.12902. Epub 2016 Feb 22.


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.

Keywords: logopenic progressive aphasia; meta-analysis; primary progressive aphasia; progressive nonfluent aphasia; semantic dementia.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't
  • Review
  • Validation Study

MeSH terms

  • Aphasia, Primary Progressive / diagnostic imaging*
  • Frontotemporal Dementia / diagnostic imaging*
  • Frontotemporal Dementia / pathology
  • Humans
  • Likelihood Functions*
  • Magnetic Resonance Imaging / standards*
  • Positron-Emission Tomography / standards*
  • Practice Guidelines as Topic / standards*
  • Primary Progressive Nonfluent Aphasia / diagnostic imaging*