Patients with signs and symptoms suggestive of dementia related to other diseases than AD or mixed forms ; Patients with progressive and unstable pathologies which could interfere with the variables under consideration ; Deafness or blindness which could compromise the evaluation of the patient or his involvement during the sessions ; Patient being under guardianship ; Patient refusing the work with a animal ; Patient allergic to dogs ; Patient ending his care prior to the 13 weeks required for the study. Exclusion criteria will be sought during the questioning of the patient and his relatives as well as the review of his medical file (organic and neuroradiological explorations).