Relationships between performance on the cogstate brief battery, neurodegeneration, and aβ accumulation in cognitively normal older adults and adults with MCI

Yen Ying Lim
Robert H. Pietrzak
Pierrick Bourgeat
David Ames
Kathryn A. Ellis
Alan Rembach
Karra Harrington
Olivier Salvado
Ralph N. Martins, Edith Cowan University
Peter J. Snyder
Colin L. Masters
Christopher C. Rowe
Victor L. Villemange
Paul Maruff

Originally published as: Lim, Y.Y., Pietrzak, R.H., Bourgeat, P., Ames, D., Ellis, K.A., Rembach, A., ... & Maruff, P. (2015). Relationships between performance on the cogstate brief battery, neurodegeneration, and aβ accumulation in cognitively normal older adults and adults with MCI in Archives of Clinical Neuropsychology, 30(1), 49-58. Available here.

Abstract

We investigated the extent to which decline in memory and working memory in beta-amyloid (Aβ) positive non-demented individuals was related to hippocampal atrophy and Aβ accumulation over 36 months. Cognitively normal older adults (CN) (n = 178) and adults with mild cognitive impairment (MCI) (n = 49) underwent positron emission tomography neuroimaging, magnetic resonance imaging, and cognitive assessments at baseline, 18- and 36-months. Relative to Aβ- CNs, Aβ+ CNs and Aβ+ MCIs showed greater rates of cognitive decline, Aβ accumulation, and hippocampal atrophy. Analysis of interrelationships between these Alzheimer's disease markers in Aβ+ CNs and MCIs indicated that rate of Aβ accumulation was associated with rate of hippocampal atrophy (β = -0.05, p =.037), which was in turn associated independently with rate of decline in memory (β = -0.03, p =.032). This suggests that Aβ accumulation precedes any neurodegeneration or clinical symptoms, and that the relationship between Aβ and cognitive decline is mediated by hippocampal atrophy.