The aim of study is to realise an objective assessment of activities "go in goal" during experimental sequence which has well-characterized acts, using at the same time an actigraphic record of activity "motive" (system of assessment indirect of apathy fit) and a video records which uses an informatic event recognition system. The assessment will realise with participants controls (n=30) and Alzheimer disease patients with (n=20) or without (n=20) apathy, during well-characterized records. The final aim is to obtain a particular assessment of some disorders behaviours, as apathy, which is principally characterize by a decrease of behaviours "to go in goal".