Memory is not enough: the neurobiological substrates of dynamic cognitive reserve

Serra, Laura, Bruschini, Michela, Di Domenico, Carlotta, Gabrielli, Giulia Bechi, Marra, Camillo, Caltagirone, Carlo, Cercignani, Mara and Bozzali, Marco (2017) Memory is not enough: the neurobiological substrates of dynamic cognitive reserve. Journal of Alzheimer's Disease, 58 (1). pp. 171-184. ISSN 1875-8908

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Abstract

Changes in the residual memory variance are considered as a dynamic aspect of cognitive reserve (d-CR). We aimed to investigate for the first time the neural substrate associated with changes in the residual memory variance overtime in patients with amnestic mild cognitive impairment (aMCI). Thirty-four aMCI patients followed-up for 36 months and 48 healthy elderly individuals (HE) were recruited. All participants underwent 3T MRI, collecting T1-weighted images for voxel-based morphometry (VBM). They underwent an extensive neuropsychological battery, including six episodic memory tests. In patients and controls, factor analyses were used on the episodic memory scores to obtain a composite memory score (C-MS). Partial Least Square analyses were used to decompose the variance of C-MS in latent variables (LT scores), accounting for demographic variables and for the general cognitive efficiency level; linear regressions were applied on LT scores, striping off any contribution of general cognitive abilities, to obtain the residual value of memory variance, considered as an index of d-CR. LT scores and d-CR were used in discriminant analysis, in patients only. Finally, LT scores and d-CR were used as variable of interest in VBM analysis. The d-CR score was not able to correctly classify patients. In both aMCI patients and HE, LT1st and d-CR scores showed correlations with grey matter volumes in common and in specific brain areas. Using CR measures limited to assess memory function is likely less sensitive to detect the cognitive decline and predict the evolution of Alzheimer's disease. In conclusion, d-CR needs a measure of general cognition to identify conversion to Alzheimer's disease efficiently.

Item Type: Article
Keywords: Dynamic cognitive reserve, memory, mild cognitive impairment, voxel-based morphometry
Schools and Departments: Brighton and Sussex Medical School > Neuroscience
Subjects: R Medicine > R Medicine (General) > R895 Medical physics. Medical radiology. Nuclear medicine
R Medicine > RC Internal medicine > RC0321 Neurosciences. Biological psychiatry. Neuropsychiatry
R Medicine > RC Internal medicine > RC0321 Neurosciences. Biological psychiatry. Neuropsychiatry > RC0346 Neurology. Diseases of the nervous system Including speech disorders
Depositing User: Patricia Butler
Date Deposited: 15 Jan 2018 08:22
Last Modified: 03 May 2018 12:29
URI: http://sro.sussex.ac.uk/id/eprint/72350

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