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Principal Investigator  
Principal Investigator's Name: Xuanning He
Institution: Australian National University
Department: Research School of Psychology
Country:
Proposed Analysis: The aim of this project is to investigate the impact of life complexity on the rate of change in cognitive abilities in late life ageing. The concept of life complexity will be developed, and operationalised through the generation of a composite variable. Analysis will focus on the variables related to current cognitive lifestyles, such as current education, current employment, and leisure activities, and variables related to participant’s cognitive performance. MRI and previous lifetime cognitive experience variables (such as prior education and employment) are needed for controlling the effect of brain atrophy, cognitive reserve, and brain reserve. Also, for generating exclusion criteria and control for other effects, other relevant variables, including demographic variables, clinical disease diagnosis, and relevant lifestyle variables, are necessary. Primarily, the collection of cognitive life experience variables will be dimensionally reduced with principle component analysis (PCA). Power analysis indicates the ADNI sample is sufficient for this (minimum n=300, 5:1sample-to-item and 19:1item-to-component ratio). We are aware of the analytical challenges posed by cognitive ageing data, including nonlinearity, heterogeneity of variance, zero hurdle and inflation, and the nature of bounded scale, and have plans to ensure appropriate modelling. The association between life experience complexity and the rate of change in cognitive function is likely to be analysed with a type of linear model based on beta distribution. Depending on the actual characteristics of the selected variables, the model will be selected and modified.
Additional Investigators