Maladie d'Alzheimer et perturbations du rythme veille-sommeil

Frequently, patients with Alzheimer's disease spend their nights in a state of restlessness and their days in a state of sleepiness. Sometimes these patients present delayed sleep phase pattern characterized by an inability to fall asleep at a desired conventional time together with an inability to awaken at a desired and socially acceptable time (they tend to fall asleep some hours after midnight and have difficulty waking up in the morning). These sleep-wake disturbances became increasingly more marked with the progression of the disease. The sleep-wake disturbances in elderly people and particularly in patients with Alzheimer's disease may result from changes at different levels: a reduction of environmental synchronizers or their perception, a lack of mental and physical activity, an age or disease related anatomical change with loss of functionality of the biological clock. In Alzheimer's disease patients, controlling sleep-wake disturbances with sedative drugs often increases both sleep disturbance and cognitive dysfunction. A chronobiological approach with bright-light therapy, melatonin administration, and sleep hygiene may be an interesting therapeutic alternative in the management of sleep-wake disorders in Alzheimer patients. The aim of these therapeutics is to improve sleep and diurnal activity, and consequently to increase the quality of life in patients with Alzheimer's disease and their caregivers.