The Effects of Apathy on Different Forms of Fatigue

60 participants with light neuro-cognitive disorders (30 apathetic, 30 non-apathetic) will be recruited from the CMRR (Centre Mémoire Ressources et Recherche) in Nice University Hospital and from the " Fragilily " Platform of the Nice University Hospital. After verification by the investigator, if they meet the inclusion criteria and sign the informed consent, participants will have to wear an actigraph for one week in order to measure their level of activity. Afterwards, participants will have to complete assessments and questionnaires to evaluate apathy (Apathy Motivation Index, Apathy Inventory), perceived fatigue (Fatigue Severity Scale, Borg scale), fatigability (6-min walking test, isometric strength test, double task), the stress level (Perceived Stress Scale) and depression (Geriatric Depression Scale). Regarding the activity level, they will also be asked to perform tasks to evaluate their kinematic movements( through an actigraph), and their particular sensitivity towards effort and reward (through serious game 'Tap-piscine'). The total duration of the evaluation is a maximum of 2 hours.