Loss of speech and functional impairment in Alzheimer's disease-related primary progressive aphasia: predictive factors of decline

Abstract

We aimed to identify features associated with different disease trajectories in Alzheimer's disease (AD)-related primary progressive aphasia (PPA). We considered 23 patients diagnosed with AD-related PPA. All patients underwent neuropsychological evaluation, ¹⁸F-Fluorodeoxyglucose-PET brain scan, CSF biomarkers measurement and APOE genotype analysis at baseline and underwent neurological follow-up for a mean time of 3 years. Patients who progressed to total loss of speech (TLoS⁺) had greater impairment in writing and higher t-tau concentration as compared to TLoS^- patients. Patients who progressed to loss of functional autonomy (LoFA⁺) had greater impairment in single-word comprehension as compared to patients who maintained autonomy in self-care. Furthermore, ¹⁸F-FDG-PET SPM analyses revealed different brain metabolic patterns between TLoS⁺ and TLoS^- and between LoFA⁺ and LoFA^-. In conclusion, linguistic profile, CSF t-tau and brain metabolic pattern might be useful tools to predict progression to total loss of speech and loss of functional autonomy in AD-related PPA patients.

Keywords: Alzheimer's disease; Amyloid biomarkers; Brain metabolism; Disease progression; Neuropsychology; Primary progressive aphasia.