Objective: To track cognitive and language changes over time in patients with logopenic (lv-PPA) and semantic (sv-PPA) variants of primary progressive aphasia (PPA).
Methods: Thirteen consecutive patients with lv-PPA and 11 patients with sv-PPA underwent yearly evaluation for a mean of 3 years. Nineteen patients (11 lv-PPA, 8 sv-PPA) had Pittsburgh compound B PET scans. Outcome variables included the Mini-Mental State Examination, Addenbrooke's Cognitive Examination-revised (ACE-R) with its 5 cognitive subscores, and 3 language tasks based on single word processing. Mixed-models regressions were used to estimate the differential rate of decline between cohorts.
Results: Despite equivalent level of baseline impairment, the lv-PPA cohort showed more rapid and generalized cognitive decline that involved nonverbal domains, with the majority of cases meeting criteria for dementia within 12 months. By contrast, cognitive changes in the sv-PPA cohort were slower and remained confined to verbally mediated tasks.
Conclusions: Patients with lv-PPA are on the cusp of global dementia that typically develops quite rapidly, contrasting with the long period of circumscribed semantic impairment seen in patients with sv-PPA. The ACE-R appears capable of monitoring decline, which is relevant to therapeutic trials.