Until recently, Alzheimer’s disease (AD) diagnosis was clinical, which had limitations. Currently, biomarkers have been developed to increase the certainty of diagnosis, also allowing earlier identification, diagnosis, and treatment. On the other hand, clinical syndromes like subjective cognitive decline (SCD; subjective perception of cognitive decline in the absence of cognitive impairment in neuropsychological testing) and mild cognitive impairment (MCI; cognitive deficits with preservation of activities of daily living) are useful to identify subjects in predementia stages with increased risk of Alzheimer’s dementia. Hence, AD is currently defined as a biological construct by using biomarkers as proxies of pathology, while the clinical consequences of the disease (i.e., symptoms) are used to stage it, enabling the identification of pre-symptomatic AD. Unfortunately, there are factors limiting the generalization of an efficient use of biomarkers in daily clinical practice, such as the lack of generalized access, high degree of invasiveness or elevated costs, hampering both the diagnostic and trial recruitment of early symptomatic or pre-symptomatic subjects for early interventions. New research indicates that digital devices enabling the collection of frequent or continuous, objective, and multidimensional data during daily activities may capture subtle changes in cognition and functional capacity long before the onset of cognitive decline. Here, we aim to test a novel mobile phone and tablet-based, digital biomarker platform that evaluates cognition through a user-friendly exercise that simulates a complex activity of daily living (Altoida). Throughout the present project, we propose to show the usefulness of this platform for detecting individuals at high AD risk, in SCD and MCI subjects, hence being able to ecologically triage SCD and MCI at higher risk for AD, and for tracking disease progression in both SCD and MCI patients, potentially becoming a trial outcome. SCD and MCI subjects will be recruited from ongoing studies at the partner organizations.