The Cambridge Centre for Ageing and Neuroscience (Cam-CAN) longitudinal study protocol: Phase 4 ('Enrichment') and Phase 5 ('Rescan')

BackgroundThe Cambridge Centre for Ageing and Neuroscience (Cam-CAN) started in 2010 to study the effect of healthy adult ageing on cognition and the brain in a population-derived sample. The study design and protocol for Phases 1-3 of Cam-CAN were detailed in Shafto et al. (2014); this paper outlines the design and protocol of Phases 4-5, which enable longitudinal investigation of cognitive and brain ageing over approximately 12 years. More details about the Cam-CAN project can be found here: www.cam-can.org. Methods/DesignPhase 4 was an at-home assessment of cognition, demographics and lifestyle, performed approximately 6 years after Phase 1 (baseline assessment), for which all people from Phase 1 were invited. Phase 5 combined repeated online cognitive, demographics and lifestyle assessment, followed by in-lab attendance for MRI and MEG brain scanning, approximately 12 years after Phase 1, for which all people from Phase 2 (baseline brain assessment) were invited. Demographics, lifestyle and cognitive data are therefore now available for three timepoints, and MRI and MEG brain data for two timepoints. DiscussionThe Cam-CAN study offers deep and wide phenotyping of neurocognitive health across the adult lifespan (18-96). These rich data will allow researchers to address questions like: why do some people maintain their cognitive abilities better than others, in terms of their brain structure or function, their lifestyle and/or their genetics? Given the shifting demographics towards old age in most countries, this knowledge will be important to help people function independently for longer, reducing both individual and societal burden.