English summary: Alzheimer's disease not only worries and distresses its victims, but shatters their lives. It challenges their personal identity and particularly their autonomy, altering their lives in terms of choices, relationships with others, and the ability to express desires and even thoughts. It imposes on them new rules of thought and decision-making, demanding that the environment and other people adapt to their new way of life. This book presents the questions raised by various actors (doctor, nursing staff, psychologist, sociologist, philosopher, and jurist) on this difficult issue and the problems it creates. What conception of this illness do people have? When first diagnosed with the disease, how do they react? How much weight should our societies, institutions and public health projections give to the status of a so-called "demented" individual? What kind of support should be extended to patients deemed to be "deprived" of their identity and of some of their rights? The challenge of such pluridiciplinary deliberation is partly epistemological - in that it exposes the gap existing between how the illness is perceived, its scientific formulation and its experienced reality - and partly ethical, in that it calls for making a clear distinction between the patient's entry into a dependent state and loss of autonomy. This book advocates a respect for autonomy that will motivate caregivers and attendants to listen more closely, be more confident, show greater sensitivity, encourage exchanges, and offer more understanding and concern. French description: La maladie d'Alzheimer inquiete, angoisse, bouleverse. Elle remet en question l'identite personnelle et notamment l'autonomie, alterant l'existence en termes de choix, de relation a l'autre, d'expression de la volonte et de la pensee. Elle impose aux sujets malades de nouvelles regles de pensee et de decision elle demande une adaptation du milieu et des autres a ce nouveau mode d'etre. Ce livre reunit les interrogations de differents acteurs (medecin, cadre infirmier, psychologue, sociologue, philosophe, juriste) sur cette question difficile et les problemes qui en decoulent. Quelle representation se fait-on de la maladie ? Que va susciter son annonce ? Quelleplace nos societes, nos institutions, nos previsions de sante publique peuvent-elles accorder au statut de la personne dite demente Que peut etre l'accompagnement d'un patient dont on pense qu'il est dechu de son identite et d'une partie de ses droits ? L'enjeu de cette reflexion pluridisciplinaire est d'une part epistemologique, en exposant l'ecart existant entre l'image de la maladie, sa conception scientifique, la realite vecue, et d'autre part ethique, en invitant a ne pas confondre entree dans la dependance et perte d'autonomie. Cet ouvrage defend le principe d'un respect de l'autonomie propre a motiver soignants et aidants vers plus d'ecoute, de confiance, de nuances, d'echanges, de comprehension et de sollicitude.