Contribution of four lifelong factors of cognitive reserve on late cognition in normal aging and Parkinson's disease.
BACKGROUND
Cognitive reserve (CR) was proposed to explain how individual differences in brain function help to cope with the effects of normal aging and neurodegenerative diseases. Education, professional solicitations, and engagement in leisure and physical activities across the lifetime are considered as major determinants of this reserve.


METHODS
Using multiple linear regression analyses, we tested separately in healthy elderly and Parkinson's disease (PD) populations to what extent cognitive performance in several domains was explained by (a) any of these four environmental lifespan variables; (b) demographic and clinical variables (age, gender, depression score, and, for the PD group, duration of disease and dopaminergic drugs). We also tested for an interaction, if any, between these lifespan variables and brain pathology indexed by global atrophy measured from high-resolution anatomical magnetic resonance imaging.


RESULTS
Age was negatively associated with cognitive performance in the PD group. In healthy elderly participants, we observed significant positive associations between cognitive performance and (a) education, (b) leisure activities, and (c) professional solicitation (decisional latitude). Furthermore, participants with greater brain atrophy benefited more from CR. In PD patients, education and professional solicitations contributed to cognitive performance but to a lesser extent than in controls. CR factors modulated the relationship between cognition and brain atrophy only in patients with a slight or moderate brain atrophy.


CONCLUSIONS
Education is the CR factor that contributed the most to late cognitive functioning in both groups, closely followed by leisure activity in normal aging and professional solicitations in PD. Our results also provide evidence suggesting that the effects of CR does not express similarly in normal aging and PD. From a broader perspective, these results seem to indicate that CR factors the most consistently practiced across lifespan (education and professional solicitation) are those that are the more strongly associated to late cognitive efficiency.
a GIGA-CRC In Vivo Imaging, University of Liège , Liège , Belgium.|b Centre de Recherches sur la Cognition et l'Apprentissage (UMR CNRS 7295), Sport Sciences Faculty , University of Poitiers , Poitiers , France.
Maud
M
Rouillard
b Centre de Recherches sur la Cognition et l'Apprentissage (UMR CNRS 7295), Sport Sciences Faculty , University of Poitiers , Poitiers , France.
Michel
M
Audiffren
b Centre de Recherches sur la Cognition et l'Apprentissage (UMR CNRS 7295), Sport Sciences Faculty , University of Poitiers , Poitiers , France.|c Laboratoire Sciences de la Cognition, Technologie, Ergonomie (SCoTE) , University of Toulouse, INU Champollion , Albi , France.
Cédric
C
Albinet
a GIGA-CRC In Vivo Imaging, University of Liège , Liège , Belgium.
Mohamed
M
Ali Bahri
a GIGA-CRC In Vivo Imaging, University of Liège , Liège , Belgium.|d Department of Neurology , CHU of Liège , Liège , Belgium.
Gaëtan
G
Garraux
a GIGA-CRC In Vivo Imaging, University of Liège , Liège , Belgium.|e Psychology and Cognitive Neuroscience Research Unit , University of Liège , Liège , Belgium.
Fabienne
F
Collette
D000368:Aged; D000375:Aging / Q000523:psychology*; D001284:Atrophy / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology; D001921:Brain / Q000000981:diagnostic imaging*; D003071:Cognition / Q000502:physiology*; D058245:Cognitive Reserve / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000000981:diagnostic imaging / Q000523:psychology*
Aging; Brain atrophy; Cognition; Cognitive reserve; Education level; Leisure activities; Occupation; Parkinson’s disease; Physical activity