[Sleep and dementias]

Abstract

Objective: A description of sleep-wake disorders in Alzheimer's disease and Creutzfeldt-Jakob disease, and analysis of their diagnostic usefulness.

Development: Patients with Alzheimer's disease have fragmented sleep, with an increase in the time awake and reduction in deep slow sleep and REM sleep. These changes increase as the disease progresses and cognition deteriorates. In Creutzfeldt-Jakob's disease polysomnographic studies show a cyclical pattern and theta or theta-delta activity. These cyclical changes are modified as the disease progresses and disappear before death.

Conclusions: Alterations in sleep are usual in patients with moderate or severe Alzheimer's disease; these alterations non-specific and insufficient to establish an early diagnosis. In the initial phase of Creutzfeldt-Jakob's disease, there are constant alterations in sleeping-waking preceding the periodic complexes seen during waking. Subsequently, as the disease progresses, specific cyclical changes appear.