Sleep-related complaints, particularly insomnia and wakefulness at nig
ht, are common. The causes are multiple, and include normal, if not id
eal, changes in sleep stages and organization with age. The prevalence
of sleep disorders is also known to increase with advancing age. Thes
e factors are even more exaggerated in the sleep of older individuals
who suffer from dementia, and may account for nocturnal agitation in t
his group.