What is normal sleep in the elderly?

Changes in the sleep and daytime alertness of the elderly are common and are secondary to a variety of causes. These changes cannot be attributed solely to the aging process. The role of occult sleep disorders in producing these changes in significant, and severe sleep disruption in the healthy elderly is almost always secondary to a sleep disorder such as sleep apnea. A number of precautions must be kept in mind when interpreting studies of sleep in the elderly.