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Utilizing Repetitive Transcranial Magnetic Stimulation to Improve Language Function in Stroke Patients with Chronic Non-fluent Aphasia

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Rates of Amyloid Imaging Positivity in Patients With Primary Progressive Aphasia.

Miguel A Santos-Santos^1,2,3,4, Gil D Rabinovici^1,5, Leonardo Iaccarino^1,6

¹Department of Neurology, Memory and Aging Center, University of California San Francisco.

|January 9, 2018

Summary

Predicting neurodegenerative pathology is crucial for targeted therapies. This study found that logopenic variant primary progressive aphasia (PPA) is strongly associated with amyloid positivity, while semantic and nonfluent/agrammatic variants are typically amyloid-negative.

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Area of Science:

Neuroscience
Neurology
Medical Imaging

Background:

Accurate prediction of neurodegenerative pathology is vital for developing targeted therapies.
Primary progressive aphasia (PPA) presents with distinct clinical variants, each potentially linked to different underlying pathologies.

Purpose of the Study:

To determine the rates of amyloid positivity using positron emission tomography (PET) in the main clinical variants of primary progressive aphasia (PPA).

Main Methods:

A prospective clinical-pathologic case series of 89 PPA patients evaluated between 2002 and 2015.
Inclusion criteria involved clinical PPA diagnosis, comprehensive language/cognitive testing, MRI, and amyloid PET scans (PiB or florbetapir F-18).

Main Results:

Logopenic variant PPA showed high amyloid positivity (96%), contrasting with semantic (86% negative) and nonfluent/agrammatic variants (90% negative).
Autopsy data confirmed Alzheimer disease pathology in amyloid-PET positive logopenic variant PPA and mixed pathology in some amyloid-PET positive semantic/nonfluent PPA cases.

Conclusions:

PPA variant diagnosis correlates with Alzheimer disease biomarker status, particularly the logopenic variant's high association with amyloid positivity.
In cases clinically suggesting frontotemporal lobar degeneration, Alzheimer disease biomarker positivity may indicate mixed pathology rather than pure Alzheimer disease.