Alzheimer's disease (AD) is a brain disorder that affects a person's thoughts, memory, speech, and ability to carry out daily activities. With AD the loss of brain tissue that leads to loss of mental abilities may also disrupt the sleep/wake cycle, which may cause sleep problems, nighttime wandering, and agitation.
AD affects an estimated 4.5 million Americans, according to the National Institute on Aging at the National Institutes of Health. Alzheimer's disease is not a normal part of aging but the risk of developing it goes up with age. It usually begins after age 60 and the risk nearly doubles with every 5 years of age after age 60, according to the U.S. Surgeon General. Because of the "graying" of Americans, the number of Alzheimer's patients is expected to increase dramatically in the coming years.
The amount of sleep disruption in AD patients usually depends on the stage of their disease. Patients in the early stages of AD may sleep more than usual or wake up disoriented. As the disease progresses, patients may begin to sleep during the day and awaken frequently throughout the night.
Patients with more advanced AD rarely sleep for long periods. Rather, they doze irregularly throughout the day and night. Circadian rhythms - daily cycling of body temperature, sleep, wakefulness, and metabolism - are sometimes disrupted in older adults. Evidence suggests that these disruptions may be worse in patients with AD and that AD patients may lose the ability to stay asleep or keep alert as the disease progresses. Sleep problems may also increase agitation among AD patients, according to the results of at least one study.
Another feature of AD is "sundowning," a term used to describe an increase in agitated behavior that occurs in the evening. This increased agitation may be explained by sleepiness or it may be that agitated behavior is more troublesome to caregivers after sun down. Whatever their causes, agitation and sleep problems result in severe stress for caregivers and are among the top reasons AD patients are given care in nursing homes instead of at home.
AD may also be linked genetically with obstructive sleep apnea (OSA). In a recent study, researchers at Stanford University Medical Center found that a gene associated with OSA is also associated with a higher risk of AD and other chronic illnesses such as heart disease. These results highlight the complexity of AD and shed light on the need to treat the range of symptoms associated with it in order to offer patients the best possible quality of life.
Sleep problems also affect the physical and mental health of people who care for AD patients. In one recent study, researchers found an increased risk of heart disease for elderly caregivers of AD patients. In addition, sleep problems among caregivers increases the likelihood of AD patients being cared for in an institutional facility, a decision that may ultimately permit a healthier life for both the caregiver and the patient.
Symptoms of AD develop slowly, usually beginning with short term memory problems. Over time, patients gradually lose more and more of their mental capabilities. For example, they may have difficulty remembering people or events and then lose the ability to do everyday tasks such as cooking, cleaning, and bathing. Eventually, AD patients may not be able to recognize loved ones, speak, or think clearly.
Another primary symptom of AD is a disrupted sleep/wake cycle, which causes patients to be sleepy during the daytime and alert and restless at night. Because caregivers are likely to be asleep during the night when AD patients are active, sleep/wake disruptions can be a dangerous problem for AD sufferers. In addition, AD patients who do not get enough sleep are more likely to suffer from agitation.
Additional symptoms of AD include:
There is no cure for AD, but there are behavioral and drug therapies that may slow its progression and treat its symptoms. For example, cholinesterase inhibitors are medications used to treat mild to moderate AD. They work by blocking the action of an enzyme that breaks down acetylcholine, a chemical which is essential to brain function. In addition, a drug called memantine is used to treat moderate to severe AD. It works by regulating glutamate, a chemical in the brain that is important to learning and memory. AD patients may also benefit from antidepressant, antipsychotic, and sedating medications.
Drug therapies can improve symptoms in some patients, but behavioral approaches to treating AD are also very effective and should be an essential part of a disease management program. For example, memory training may help AD patients with forgetfulness and psychotherapy may alleviate symptoms of depression. Getting adequate sleep on a regular schedule is also critical to the management of AD symptoms. Behavioral therapies, including those for sleep problems, also target families and caregivers of AD patients and can be an important part of the treatment plan for AD. If nighttime awakening is a problem, try to avoid or curtail naps.
The National Institute on Aging at the National Institutes of Health identifies many forms of dementia, all of which have many of the same effects as Alzheimer's disease. AD is the most prevalent form of dementia, though the second leading cause of impaired cognitive function in older adults is multi-infarct dementia which is actually caused by a series of often imperceptible strokes. Some forms of dementia may be cured or managed if accurately diagnosed and treated. That is why it is important to actively seek out answers to signs of memory loss.
According to NSF's 2003 Sleep in America poll adults with memory problems are more likely than those without memory problems to experience symptoms of insomnia, such as difficulty falling asleep, waking a lot during the night, and waking too early. While waking up a lot in the middle of the night is the most common insomnia complaint, the biggest overall problem disrupting the sleep of older adults is the need to get up and go to the bathroom, with nearly two thirds (65%) reporting this disturbance at least a few nights a week.
Reviewed by Michael Vitiello, PhD, and Andrew Monjan, PhD, MPH.