Sleep is a vital physiologic process with important restorative functions. Notable qualitative and quantitative changes in sleep occur with age. Moreover, many sleep-related disorders occur with increasing frequency among elderly people. These conditions are often not appreciated by physicians, the associated symptoms ascribed instead to coexistant medical illness. In part 1 of this review, we attempt to summarize several of the most important sleeprelated disorders commonly observed in older patients. In the forthcoming part 2, we will highlight the principles of treatment of these conditions.
Age-related sleep changesNormal sleep progresses through several stages in a predictable fashion (Table 1). This cycle repeats several times during the sleep period. With age, important changes in sleep structure occur (Box 1); 1 perhaps most characteristic is a phase advance of the normal circadian cycle. The result is a propensity toward an earlier sleep onset, accompanied by an earlier morning wake signal. Thus, elderly people often go to bed early and report being early risers. With aging, the total amount of time asleep shortens: infants and young children sleep an average of 16-20 hours per day; adults, 7-8; and people over 60 years of age, 6 1 /2 hours daily.2 Delta sleep (stages 3 and 4), the deepest and most refreshing form of sleep, diminishes with age.
2
Sleep pathologies in older patients InsomniaInsomnia, defined as difficulty falling or staying asleep, is frequent in older people.1,2 In some patients, insomnia can be caused by an underlying medical condition or a medication side effect (secondary insomnia). In the absence of a causative factor, it is referred to as primary insomnia. Monane 3 has estimated that insomnia affects nearly half of all those over the age of 65 years. Elderly women tend to report sleep disturbances more frequently than elderly men.4 The sleep changes noted among older women may be partly related to changes in the postmenopausal profile of sex hormones. Estrogen deficiency in particular has been postulated to contribute to the sleep difficulties that women often begin to experience in their perimenopausal period, and then increasingly with age.
5Frequent awakenings are particularly common among elderly people and may be related to their more frequent incidences of concurrent medical conditions. Among the most common causes of secondary insomnia are a variety of musculoskeletal disorders, nocturia related to benign prostatic hypertrophy in men and bladder instability with decreased urethral resistance in women, congestive heart disease, and chronic obstructive lung disease.Depression and anxiety disorders, common among people over 65 years of age, frequently contribute to insomnia.
6Risk factors for depression in older people include loss of a spouse, retirement, social isolation, comorbid disease and onset of dementia.Sleep disturbance or disruption is common among patients experiencing dementia, particularly those with Alzheimer's disease.7 Such patients often have difficulty not on...