This thesis contributes to dementia research by employing machine learning techniques, specifically focusing on facial emotion recognition to investigate emotional states as possible early markers of dementia. Dementia is one of the major causes of disability and dependency among older people worldwide and is the seventh leading cause of mortality on a global scale. Receiving a timely diagnosis enables patients and caregivers to enhance their quality of life and get the opportunity to participate in clinical trials. For an early detection of dementia disease, a precursor stage of dementia known as Mild Cognitive Impairment is investigated. In this phase, the first symptoms occur, as memory loss, trouble concentrating, disorientation, communication issues, and changes in mood and behaviour, but the daily activities are still not compromised.