HealthDay News — Individuals with primary progressive aphasia (PPA) associated with Alzheimer disease (AD) have longitudinally preserved episodic memory, according to a study published online Jan. 13 in Neurology.
M. Marsel-Mesulam, M.D., from the Northwestern University Feinberg School of Medicine in Chicago, and colleagues examined whether memory is preserved longitudinally in PPA-AD. Longitudinal memory assessments were performed in 17 PPA patients with evidence of AD on autopsy or biomarkers and in 14 patients with amnestic dementia of the Alzheimer type with AD at autopsy (DAT-AD).
The researchers found that episodic memory was preserved at initial testing in PPA-AD and showed no decline at retesting 2.35 ± 0.78 years later, at which point symptoms had been present for 6.26 ± 2.21 years. During the same period, language functions declined significantly. Both verbal memory and language declined with equal severity in DAT-AD. Asymmetric left-sided mediotemporal atrophy was seen in imaging in PPA-AD, but autopsy revealed bilateral hippocampo-entorhinal neurofibrillary degeneration at Braak stages V and VI. The PPA-AD group had a lower incidence of apolipoprotein E4 and of mediotemporal TDP-43 pathology compared with DAT-AD.
“More research is needed to help us determine what factors allow these people to show this resilience of memory skills even in the face of considerable Alzheimer’s disease pathology in the brain,” Mesulam said in a statement.
18F-florbetapir doses were provided by Avid Radiopharmaceuticals.