Apathy in Late Life Depression: New Biomarkers Using Actimetry and Magnetic Resonance Imaging

Old age (\> 60 years) is at high risk to develop major depression disorders (MDD). MDD doubles the risk for subsequent cognitive disorders and dementia. Apathy (i.e. the lack of motivation) is a core problem in depression in older age and is frequently associated with cognitive decline in people who have mild cognitive disorders. The investigator propose here to combine actimetry (the measurement of motor activity using a simple device worn at the wrist) and brain imaging to show that it's possible to measure apathy using actimetry in a population of elders with MDD. Having shown that apathy can reliably be measured with actimetry and that it is associated with brain abnormalities, the investigator will be able to test whether actimetry can predict cognitive decline in elders with MDD and can be routinely used in a day-to-day medical practice.