Amyloid and FDG-PET study of logopenic primary progressive aphasia: evidence for the existence of two subtypes.

Abstract

The logopenic variant of primary progressive aphasia (lvPPA) has been associated with Alzheimer disease, although this relationship is still subject to debate. The purpose of this study is to determine the frequency of amyloid biomarkers in patients with lvPPA, and record any potential clinical or topographic differences between patients with and without amyloid deposits. We conducted cognitive examination and positron-emission tomography studies with fluorodeoxyglucose ((18)F) and florbetapir ((18)F) in a cohort of 16 patients diagnosed with lvPPA. We evaluated the prevalence of amyloid deposits as well as any clinical and metabolic differences between the groups with and without significant presence of amyloid deposits. Eleven patients (69 %) were considered amyloid-positive. The amyloid-positive group displayed less metabolic activity in the left temporoparietal region than the control group, while the amyloid-negative group showed lower metabolism in the left temporoparietal region extending to the anterior temporal and basal frontal regions. The percentage of change in patients with clinical and FDG-PET follow-up did not differ between the amyloid-positive and amyloid-negative subgroups. The frequency of amyloid-positive cases confirms that lvPPA is frequently associated with Alzheimer disease. Amyloid-negative patients show a different cerebral metabolic pattern. These findings show the relevance of using amyloid PET to study lvPPA, and also suggest that the logopenic variant may not be specific to Alzheimer disease in certain cases.

• Authors: Jordi A Matías-Guiu, María Nieves Cabrera-Martín, Teresa Moreno-Ramos, María Valles-Salgado, Marta Fernandez-Matarrubia, José Luis Carreras, Jorge Matías-Guiu
• Journal: Journal of neurology (J Neurol) Vol. 262 Issue 6 Pg. 1463-72 (Jun 2015) ISSN: 1432-1459 [Electronic] Germany
• PMID: 25860346 (Publication Type: Journal Article)

Chemical References

• Amyloid
• Fluorodeoxyglucose F18

Topics

• Aged
• Aged, 80 and over
• Amyloid (metabolism)
• Aphasia, Primary Progressive (classification, complications, diagnostic imaging, metabolism)
• Brain Mapping
• Cognition Disorders (etiology)
• Female
• Fluorodeoxyglucose F18
• Humans
• Longitudinal Studies
• Male
• Middle Aged
• Neuropsychological Tests
• Positron-Emission Tomography
• Statistics, Nonparametric
• Tomography, X-Ray Computed