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Dementia is a slowly progressive brain disorder characterized by the loss of ability to think, reason and remember. In Lewy body dementia, abnormal round structures — called Lewy bodies — develop in regions of your brain involved in thinking and movement.

Lewy body dementia shares characteristics with both Alzheimer's disease and Parkinson's disease. Like Alzheimer's, it causes confusion. It may also cause distinctive physical signs typical of Parkinson's — rigid muscles, slowed movement and tremors. Lewy body dementia can also cause hallucinations.

There's no cure for Lewy body dementia — although some people with this disease benefit from drugs developed for Alzheimer's disease. Treatment focuses on managing the signs and symptoms.

It's important that your doctor distinguishes Lewy body dementia from other forms of dementia in creating a treatment plan. This is because some medications used to treat psychiatric symptoms may actually worsen Lewy body symptoms such as hallucinations and delusions.

Visual hallucinations, such as seeing colors, shapes, animals or people, may be one of the first symptoms of Lewy body dementia. Other signs and symptoms are similar to those of both Parkinson's disease and Alzheimer's disease.

Parkinson's-like signs
These may include:

• Slowed movement
• Rigid muscles
• Tremors
• Shuffling walk

Alzheimer's-like signs and symptoms
Such symptoms could include:

• Confusion
• Memory loss
• Decreased or irregular awareness or reasoning (cognition)
• Delusions such as false ideas about another person or situation
• Depression

People with Lewy body dementia often experience fluctuating alertness, for example, being alert midmorning, then drowsy or inattentive by the end of the morning.

Another indicator of Lewy body dementia may be a strong reaction — such as worsening delusions and hallucinations — to the medications normally used to treat those symptoms. The reaction to these medications can be debilitating and even life-threatening in those who have this disease, for example causing muscle rigidity, loss of cognition or even catatonia — a condition of either motionless apathy or constant excitement.

Still other signs include REM sleep behavior disorder — which involves acting out your dreams — and signs of dysfunction of the autonomic nervous system, which regulates involuntary muscle movements. Dysfunction of the autonomic nervous system can result in poorly regulated blood pressure, sweating and body temperature.

The cause of Lewy body dementia isn't known. However, Lewy bodies contain a protein associated with Parkinson's. In addition, Lewy bodies often are found in the brains of people who have Parkinson's or Alzheimer's. This suggests that the three conditions are related or that Lewy body dementia and Alzheimer's or Parkinson's disease sometimes coexist in the same person.

Although the cause of Lewy body dementia isn't clear, several factors appear to increase the risk of developing the disease:

• Age. Most cases of Lewy body dementia occur in adults between the ages of 50 and 85.
• Heredity. If you have a family member with Lewy body dementia, you may be at increased risk of the disease.

No single test can diagnose Lewy body dementia. Instead, doctors diagnose the disease through a process of elimination — ruling out other diseases and conditions that also can cause similar signs and symptoms.

To assess a person's condition, doctors typically use the following:

• Medical history. Doctors may ask about a person's general health and past medical problems. They'll want to know about any problems a person may have in carrying out daily activities. If possible, doctors will also want to speak with a person's family or friends to get more information.
• Basic medical tests. Blood and urine tests may be done to help doctors rule out other potential causes of the dementia. In some cases, testing a small amount of spinal fluid may help indicate something other than dementia. For example, signs of inflammation may suggest infection, or certain proteins may suggest cancer, an autoimmune disorder, or Creutzfeldt-Jakob disease, a degenerative brain condition.
• Mental status evaluation. These tests screen memory, problem-solving abilities, attention spans, counting skills and language. They help doctors pinpoint specific problems a person may have with cognition. For instance, doctors might test recent and long-term memory by asking: What day is it today? Or: When was World War II? Recall tests are another example. Doctors may list familiar objects, and then ask a person to repeat them immediately, and again five minutes later.
• Neuropsychological testing. Sometimes doctors undertake a more extensive assessment of memory, problem-solving abilities, attention spans, counting skills and language. This is especially helpful in trying to detect dementia at an early stage. Doctors use formal psychological tests to determine if a person's mental abilities are as expected for his or her age and education. The patterns of any mental deficits observed during neuropsychological testing can help doctors sort out possible causes of dementia.
• Brain scans. Doctors may want to take an image of the brain using a brain scan. Several types of brain scans are available — including a computerized tomography (CT) scan, a magnetic resonance imaging (MRI) scan and a positron emission tomography (PET) scan. A CT scan is an X-ray technique that produces more detailed images of your internal organs than do conventional X-ray exams. An MRI uses a magnetic field and radio waves to create cross-sectional images of the inside of your body. PET scans show images containing areas of more or less intense color (a radioactive tracer injected into your body) to provide information about chemical activity within certain organs and tissues. By looking at an image of the brain, doctors may be able to pinpoint any visible abnormalities.

Making the diagnosis
For the doctor to make a diagnosis of Lewy body dementia, he or she must observe a progressive decline in ability to think (decreased cognition) as well as two of the following:

• Fluctuating alertness and cognition
• Repeated visual hallucinations
• Parkinson's-like symptoms

Other signs and symptoms of Lewy body dementia, such as REM sleep behavior disorder, dysfunction of the autonomic nervous system, and the pattern of confusion, memory loss, and delusions also may suggest this disease.

After onset, Lewy body dementia typically develops into severe dementia and ultimately eliminates a person's ability to speak or move. During the stages of the disease, which typically lasts five to seven years, people may experience complications, including fainting, alterations in blood pressure and depression.

The most common cause of death is pneumonia or another infection brought on by difficulty swallowing or inhaling food or drink into the airway, from a thin tube (catheter) inserted into the body, or from becoming bedridden.

As the disease advances, people may lose all ability to care for themselves. They may have difficulty eating, become incontinent, or be unable to take a walk and find their way back home.

These inabilities can increase the risk of additional health problems such as:

• Pneumonia. Difficulty swallowing food and liquids may cause people with Lewy body dementia to inhale some of what they eat and drink into their airways and lungs, which can lead to pneumonia.
• Infections. Urinary incontinence may require the placement of a urinary catheter, which increases the risk of urinary tract infections. Untreated urinary tract infections can lead to more serious, life-threatening infections.
• Falls and their complications. People with Lewy body dementia may become disoriented, or struggle with tremors and an impaired gait, increasing their risk of falls. Falls can lead to fractures. In addition, falls are a common cause of serious head injuries, such as bleeding in the brain. Surgery to repair injury from a fall carries risks as well. For instance, prolonged immobilization — which may be necessary to recover from injuries related to a fall — increases the risk of a blood clot in the lungs (pulmonary embolism), which can be life-threatening.

Treatment can be challenging, and there's no cure for Lewy body dementia. Instead, doctors treat the individual symptoms.

Medications

• Cholinesterase inhibitors. These Alzheimer's disease medications work by improving the levels of neurotransmitters — chemical messengers believed to be important for memory, thought and judgment — in the brain. They improve alertness and cognition and may reduce hallucinations and other behavioral problems.
• Parkinson's disease medications. These medications can help reduce Parkinson's-like motor symptoms in some people with Lewy body dementia, but they can also cause increased confusion, hallucinations and delusions.
• Antidepressants and anticonvulsants. Some antidepressants, particularly selective serotonin reuptake inhibitors, and anticonvulsants may help improve sleep and reduce anxiety, agitation and depression, but they can also increase problems with confusion, movement and sleepiness.
• Antipsychotic medications. These medications may somewhat improve delusions and hallucinations. However, they can cause problems with sleepiness, memory and cognition and increase the risk of death.

Behavioral strategies
In some cases, medications may not be necessary. For example, reducing impersonal approaches to daily tasks — such as by sponge bathing a person in bed versus giving them a bath or shower — may help reduce agitation and aggression.

Other strategies that have somewhat improved symptoms such as agitation and restlessness include physical therapy, massage, aromatherapy (using fragrant plant oils for relaxation), music therapy and pet therapy.

Problems with sleeping may improve with increased activity, reducing daily naps and caffeine intake, and delaying bedtime.

Caregiving
Until there's a cure for Lewy body dementia, people with the disease will require care. Caregiving can be a challenge. The unpredictable decline that may last more than a decade requires caregivers to exercise patience, understanding, compassion, and often, creativity.

The key to caregiving is focusing on things that the person with dementia can still do and enjoy. In fact, learning ways to reduce the impact of impaired abilities and behavior problems can help avoid some of the most difficult aspects of the disease.

Each person with dementia experiences symptoms and progression differently. Consequently, the techniques to care for each person should vary. You may have to adapt the following tips to your specific caregiving situation:

• Use memory aids. Memory aids may help a friend or family member remain independent. Write out a list of the day's activities, the phone numbers that can be used to call for help, and instructions on how to do simple tasks, such as making a cup of tea or using the telephone.
• Provide structure. A home environment that provides serenity and stability reduces behavior problems. New situations, noise, large groups of people, being rushed or pressed to remember, or being asked to do a task that's too difficult can cause anxiety. As a person becomes upset, the ability to think clearly declines even more.

• Monitor wandering. Wandering is a common problem. In some cases, a pocket card with simple instructions, such as "Call home" (with a phone number below), may help. Make sure your loved one wears a bracelet with his or her name, phone number and a notation such as "Memory impaired." The Alzheimer's Association, which has a 24-hour hot line — 800-272-3900 — offers this resource through its national Safe Return Program.

  Also try to determine the cause of wandering. It may simply be a signal that the person with dementia is looking for something, such as a bathroom, or is seeking a meaningful activity or reassurance. Some experts believe taking your loved one for a vigorous daily walk helps reduce wandering.

• Establish a nighttime ritual. Behavior is often worse at night. Try to establish going-to-bed rituals that are calming and away from the noise of television, meal cleanup and active family members. Leave night lights on to prevent disorientation. Limiting caffeine during the day, discouraging daytime napping and offering opportunities for exercise during the day may help prevent nighttime restlessness.
• Enhance communication. When talking with your loved one, stand where you can be seen and touch his or her arm or shoulder to focus attention. Speak slowly, in simple sentences and don't rush the response. Present only one idea or instruction at a time. Use gestures and cues, such as pointing to objects. Avoid asking questions or offering difficult choices because trying to come up with answers may prove frustrating.
• Create a safe environment. Make your home familiar and safe. Keep furniture in the same place to avoid clutter and help prevent falls. Install locks on cabinets containing medicines, alcohol, guns, toxic substances, and dangerous utensils and tools. Remove electrical appliances from your bathroom to prevent shocks, set your water heater no higher than 120 F to prevent scalding, and install grab rails to prevent falls.
• Encourage exercise. Exercise carries many benefits. The fact that these benefits often are the same for people without dementia doesn't lessen their importance. In fact, it just makes exercise a more important activity for caregivers and people with dementia to engage in together. The main benefits of exercise include improved strength and cardiovascular health. Exercise can also lessen symptoms of depression, help retain motor skills and create a calming effect. It can also help sustain strength, flexibility and balance — which may lessen the risk of serious injury from a fall.

Long-term considerations
In addition to helping a loved one with Lewy body dementia deal with daily challenges, you'll need to begin to try to answer practical, long-term questions about caregiving as soon as possible. These questions may involve personal, legal and financial issues. Some examples might include:

• Level of self-sufficiency. How long can a person with dementia safely drive, work or live alone?
• Availability of help. Can family or friends provide the care necessary for the current phase and during later progression of the disease?
• Financial resources. Is money available for professional in-home care or a care facility now or in the future if the need arises?

Talk with your loved one's doctor to discuss these matters early on in the disease. In general, people with dementia benefit from as much independence as is safely possible and for as long as possible.

People with Lewy body dementia often experience a mixture of emotions confusion, frustration, anger, fear, uncertainty, grief and depression. You can help a person cope with the disease by being there to listen, reassuring the person that life can still be enjoyed, providing unconditional love and doing your best to help the person retain dignity and self-respect.

Caring for a person with Lewy body dementia can be an all-absorbing experience. Caregivers must watch closely to make sure the person with Lewy body dementia doesn't fall or lose consciousness or react badly to medications and must reassure that person during times of delusions or hallucinations. The person will likely also need help with daily activities.

Looking after yourself
The physical and emotional demands of caregiving can be exhausting. Feelings of anger and guilt, frustration and discouragement, worry and grief, and social isolation are common. If you're a caregiver for someone with this disease, you can help yourself and help prevent caregiver burnout by doing the following:

• Ask friends or other family members for help when you need it.
• Take care of your health.
• Learn as much about the disease as you can. Ask questions of doctors, social workers and others involved in the care of your loved one.
• Join a support group.

Many people with Lewy body dementia and their families can benefit from counseling or local support groups. Contact your local agencies on health or aging to get connected with support groups, doctors, resources and referrals, home-care agencies, supervised living facilities, a telephone help line and educational seminars.