Longitudinal Memory Profiles in Behavioral-Variant Frontotemporal Dementia and Alzheimer’s Disease

Article type: Research Article

Authors: Schubert, Samantha^a | Leyton, Cristian E.^{a; b; c} | Hodges, John R.^{a; c; d} | Piguet, Olivier^{a; c; d; *}

Affiliations: [a] Neuroscience Research Australia, NSW, Australia | [b] The Faculty of Health Sciences, The University of Sydney, NSW, Australia | [c] ARC Centre of Excellence in Cognition and its Disorders, Sydney, NSW, Australia | [d] School of Medical Sciences, The University of New South Wales, Sydney, NSW, Australia

Correspondence: [*] Correspondence to: Olivier Piguet, PhD, Neuroscience Research Australia, Barker St, Randwick NSW 2031, Australia. Tel.: +61 2 9399 1713; Fax: +61 2 9399 1047; E-mail: [email protected].

Abstract: Background:Alzheimer’s disease (AD) and behavioral-variant of frontotemporal dementia (bvFTD) can present with an overlapping neuropsychological profile, which often hinders their clinical differentiation. Objective:To compare changes over time in memory, general cognition tasks, and functional scales between bvFTD and AD. Methods:Consecutive cases diagnosed with probable bvFTD (n = 22) and typical AD (n = 31) with at least two clinical visits were selected. Of these, 13 (9 AD, 4 bvFTD) underwent Pittsburgh compound B PET scan, which supported the clinical diagnosis in all cases. Mixed-model regressions were used to estimate the differential rate of decline on selected tasks between cohorts. Results:Analyses demonstrated that, despite equivalent baseline performance, bvFTD patients experienced a more rapid functional deterioration and a steeper decline in global cognition than AD patients. At baseline, both groups were impaired on executive function and memory tasks compared to controls, but these deficits were more marked in the bvFTD group. In addition, performance on these domains continued to decline more rapidly in this group. Conclusions:Neither the initial neuropsychological assessment nor projected performances can reliably distinguish the totality of bvFTD and AD individuals. Nevertheless, annual rates of progression on cognitive tasks provide valuable information and will potentially help establish the impact of future therapeutic treatments in these dementia syndromes.

Keywords: Alzheimer’s disease, assessment of cognitive disorders/dementia, cohort study, executive function, frontotemporal dementia, memory

DOI: 10.3233/JAD-150802

Journal: Journal of Alzheimer's Disease, vol. 51, no. 3, pp. 775-782, 2016