Relations between sensory functions and Alzheimer's disease are still under-explored. To understand them better, the Fondation Médéric Alzheimer has brought together a multi-disciplinary expert group. Aristote's five senses must be enhanced by today's knowledge of proprioception, motor cognition and pain perception. When cognition breaks down, the person with dementia perceives the world around her with her sensory experience, yet is unable to integrate all this information to understand the context. The treatment of multiple sensory inputs by the brain is closely linked to cognitive processes. Sensory deficits reduce considerably the autonomy of people with dementia in their daily life and their relations with others, increase their social isolation and the risk of accidents. Professionals involved with neurodegenerative diseases remain poorly aware of sensory deficits, which can bias the results of cognitive tests. However, there are simple tools to detect these deficits, notably for vision, hearing and balance disorders, which can be corrected. Many interventions for cognitive rehabilitation or quality of life improvement are based on sensory functions. The environment of people with dementia must be adapted to become understandable, comfortable, safe and eventually therapeutic.
Keywords: Alzheimer's disease; balance; cognition; detection; hearing; pain; quality of life; rehabilitation; sensory deficits; smell; taste; vision.