Fluorodeoxyglucose F18 positron emission tomography in progressive apraxia of speech and primary progressive aphasia variants

Arch Neurol. 2010 May;67(5):596-605. doi: 10.1001/archneurol.2010.78.


Objectives: To determine patterns of hypometabolism on fluorodeoxyglucose F18 positron emission tomography (FDG-PET) in patients with progressive apraxia of speech (PAS) and primary progressive aphasia (PPA) variants and to use these patterns to further refine current classification.

Design: We identified all patients who had FDG-PET and PAS or PPA who were evaluated by an expert speech-language pathologist. Patterns of hypometabolism were independently classified by 2 raters blinded to clinical data. Three speech-language pathologists reclassified all patients into 1 of 7 operationally defined categories of PAS and PPA blinded to FDG-PET data.

Setting: Tertiary care medical center.

Patients: Twenty-four patients with PAS or PPA and FDG-PET.

Main outcome measure: Fluorodeoxyglucose F18 PET hypometabolic pattern.

Results: Of the 24 patients in the study, 9 had nonfluent speech output; 14, fluent speech; and 1 was unclassifiable. Twenty-one patients showed FDG hypometabolism; the remaining 3 did not. Among the patients showing hypometabolism, 8 had a prerolandic pattern of which 7 had nonfluent speech including progressive nonfluent aphasia (n = 3), PAS (n = 1), and mixed nonfluent aphasia/apraxia of speech (n = 3); the other patient had PPA unclassifiable. The remaining 13 had a postrolandic pattern, all with fluent speech (P < .001), including logopenic progressive aphasia (n = 6), progressive fluent aphasia (n = 6), and semantic dementia (n = 1). Patterns of hypometabolism differed between the nonfluent variants and between the fluent variants, including progressive fluent aphasia.

Conclusion: Patterns of FDG-PET hypometabolism support the clinical categorizations of fluency, the distinction of apraxia of speech from progressive nonfluent aphasia, and the designation of a progressive fluent aphasia category.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Aphasia, Primary Progressive / diagnostic imaging*
  • Aphasia, Primary Progressive / metabolism
  • Aphasia, Primary Progressive / physiopathology*
  • Apraxias / diagnostic imaging*
  • Apraxias / metabolism
  • Apraxias / physiopathology*
  • Brain / diagnostic imaging*
  • Brain / metabolism
  • Brain / physiopathology*
  • Brain Mapping
  • Cohort Studies
  • Diagnosis, Differential
  • Energy Metabolism / physiology
  • Female
  • Fluorodeoxyglucose F18
  • Functional Laterality / physiology
  • Humans
  • Language Tests
  • Male
  • Middle Aged
  • Positron-Emission Tomography
  • Predictive Value of Tests


  • Fluorodeoxyglucose F18