Alzheimer's Disease and Other Dementias

Sleep anomalies are found in a variety of conditions causing dementia. Specific features of the sleep and electroencephalographic impairments vary in some respects, but a common pattern emerges. Sleep is usually more fragmented, both from more awakenings and from a longer duration of time awake; slow-wave sleep is decreased; spindles and K-complexes are less well formed or less numerous, so sleep stages are more difficult to distinguish; and rapid eye movement (REM) sleep may be reduced. Quantitative analyses show a slowing of the electroencephalogram (EEG) during wakefulness and, in Alzheimer's disease, during REM sleep. These impairments typically worsen with the progression of the disease. Demented patients are also more likely to present with periodic limb movements in sleep and respiratory disturbances. This chapter gives an overview of sleep disturbances, characteristics of sleep architecture and microstructure, and quantitative analyses of wakefulness and sleep EEG in a variety of conditions associated with dementia: Alzheimer's disease, progressive supranuclear palsy, Parkinson's disease, dementia with Lewy bodies, vascular dementia, Huntington's disease, Creutzfeldt-Jakob disease, and frontotemporal dementia.