Sub-study 1: Cross-sectional study design: From two established cohorts with pre-existing datasets of up to 10 years of longitudinal cognitive, genetic and demographic data, the team will recruit 500 participants over 50 years old who are confirmed to have normal cognition. At baseline and months 3 and 6, the participants will be invited to complete TAS Test online at home, or in the research centre if preferred. The participants will also have a baseline blood test for ptau181 levels (and APOE4 if required). The research team will integrate movement data to develop a multivariable model that discriminates between pre-AD (positive p-tau181) and normal cognitive ageing (negative p-tau181).
Sub-study 2: Prospective 5-year cohort study design: The researchers will invite 10,000 adults from an established long-term (ISLAND Project) cohort to complete online tests at home: (i) TAS Test every 6 months, and (ii) Cambridge Neuropsychological Test Automated Battery (CANTAB) cognitive tests every 24 months. The prospective 'high risk' predictions of TAS Test at baseline will be validated against CANTAB scores, and also clinically (face to face gold standard consensus diagnosis of AD vs MCI vs normal) in a subsample of 300.
