Lewy body dementia, also known as dementia with Lewy bodies, is the second most common type of progressive dementia after Alzheimer's disease. Protein deposits, called Lewy bodies, develop in nerve cells in the brain regions involved in thinking, memory and movement (motor control).

Lewy body dementia causes a progressive decline in mental abilities. People with Lewy body dementia might have visual hallucinations and changes in alertness and attention. Other effects include Parkinson's disease signs and symptoms such as rigid muscles, slow movement, walking difficulty and tremors.

Lewy body dementia signs and symptoms can include:

• Visual hallucinations. Hallucinations — seeing things that aren't there — might be one of the first symptoms, and they often recur. People with Lewy body dementia might hallucinate shapes, animals or people. Sound (auditory), smell (olfactory) or touch (tactile) hallucinations are possible.
• Movement disorders. Signs of Parkinson's disease (parkinsonian signs), such as slowed movement, rigid muscles, tremor or a shuffling walk can occur. This can lead to falling.
• Poor regulation of body functions (autonomic nervous system). Blood pressure, pulse, sweating and the digestive process are regulated by a part of the nervous system that is often affected by Lewy body dementia. This can result in sudden drops in blood pressure upon standing (orthostatic hypotension), dizziness, falls, loss of bladder control (urinary incontinence) and bowel issues such as constipation.
• Cognitive problems. You might have thinking (cognitive) problems similar to those of Alzheimer's disease, such as confusion, poor attention, visual-spatial problems and memory loss.
• Sleep difficulties. You might have rapid eye movement (REM) sleep behavior disorder, which can cause you to physically act out your dreams while you're asleep. This might involve behavior such as punching, kicking, yelling and screaming while sleeping.
• Fluctuating attention. Episodes of drowsiness, long periods of staring into space, long naps during the day or disorganized speech are possible.
• Depression. You might develop depression.
• Apathy. You might lose motivation.

Lewy body dementia is characterized by the abnormal buildup of proteins into masses known as Lewy bodies. This protein is also associated with Parkinson's disease. People who have Lewy bodies in their brains also have the plaques and tangles associated with Alzheimer's disease.

A few factors seem to increase the risk of developing Lewy body dementia, including:

• Age. People older than 60 are at greater risk.
• Sex. Lewy body dementia affects more men than women.
• Family history. Those who have a family member with Lewy body dementia or Parkinson's disease are at greater risk.

Lewy body dementia is progressive. Signs and symptoms worsen, causing:

• Severe dementia
• Aggressive behavior
• Depression
• Increased risk of falling and injury
• Worsening of parkinsonian signs and symptoms, such as tremors
• Death, on average about seven to eight years after symptoms start

A diagnosis of Lewy body dementia requires a progressive decline in your ability to think, as well as at least two of the following:

• Fluctuating alertness and thinking function
• Repeated visual hallucinations
• Parkinsonian symptoms
• REM sleep behavior disorder, in which people act out their dreams during sleep

Autonomic dysfunction, which involves instability in blood pressure and heart rate, poor regulation of body temperature, sweating, and related signs and symptoms, supports a Lewy body dementia diagnosis. So does sensitivity to antipsychotic drugs, particularly first-generation antipsychotics such as haloperidol (Haldol). Medications like Haldol aren't used for people with Lewy body dementia because they can cause a severe reaction.

No single test can diagnose Lewy body dementia. The diagnosis is based the on signs and symptoms you have and ruling out other conditions that can cause similar signs and symptoms. Tests might include:

Neurological and physical examination

Your doctor may check for signs of Parkinson's disease, strokes, tumors or other medical conditions that can affect the brain and physical function. A neurological examination tests:

• Reflexes
• Strength
• Walking
• Muscle tone
• Eye movements
• Balance
• Sense of touch

Assessment of mental abilities

A short form of this test, which assesses your memory and thinking skills, can be done in less than 10 minutes in your doctor's office. It's not generally useful in distinguishing Lewy body dementia from Alzheimer's disease but can determine whether cognitive impairment is present. Longer tests that take several hours help identify Lewy body dementia.

Blood tests

These can rule out physical problems that can affect brain function, such as vitamin B-12 deficiency or an underactive thyroid gland.

Brain scans

Your doctor might order an MRI or CT scan to identify a stroke or bleeding and to rule out a tumor. While dementias are diagnosed based on the medical history and physical examination, certain features on imaging studies can suggest different types of dementia, such as Alzheimer's or Lewy body dementia.

If the diagnosis is unclear or the signs and symptoms aren't typical, your doctor might suggest additional imaging tests, including these that can support a diagnosis of Lewy body dementia:

• Fluorodeoxyglucose PET brain scans, which assess brain function.
• Single-photon emission computerized tomography (SPECT) or PET imaging, which can determine whether dopamine transporter uptake is reduced in the brain.

Sleep evaluation

Your doctor might order a sleep evaluation called a polysomnogram to check for REM sleep behavior disorder or an autonomic function test to look for signs of heart rate and blood pressure instability.

Heart test

In some countries, doctors might also order a heart test called myocardial scintigraphy to check the blood flow to your heart for indications of Lewy body dementia. However, the test isn't used in the United States.

Emerging biomarkers

Research is ongoing into other indicators of Lewy body dementia. These biomarkers might eventually enable early diagnosis of Lewy body dementia before the full disease develops.

There's no cure for Lewy body dementia but many of the symptoms can improve with targeted treatments.

Medications

• Cholinesterase inhibitors. These Alzheimer's disease medications, such as rivastigmine (Exelon), donepezil (Aricept) and galantamine (Razadyne), work by increasing the levels of chemical messengers in the brain (neurotransmitters) believed to be important for memory, thought and judgment. This can help improve alertness and cognition and might reduce hallucinations and other behavioral problems.

  Possible side effects include gastrointestinal upset, muscle cramps and frequent urination. It can also increase the risk of certain cardiac arrhythmias.

  In some people with moderate or severe dementia, an N-methyl-d-aspartate (NMDA) receptor antagonist called memantine (Namenda) might be added to the cholinesterase inhibitor.

• Parkinson's disease medications. These medications, such as carbidopa-levodopa (Sinemet, Rytary, Duopa) can help reduce parkinsonian signs and symptoms, such as rigid muscles and slow movement. However, these medications can also increase confusion, hallucinations and delusions.
• Medications to treat other symptoms. Your doctor might prescribe medications to treat other signs and symptoms associated with Lewy body dementia, such as sleep or movement problems.

Certain medications can worsen memory. Try to avoid over-the-counter sleep aids that contain diphenhydramine (Advil PM, Aleve PM) and medications used to treat urinary urgency such as oxybutynin (Ditropan XL).

Also limit sedatives and sleeping tablets, and talk to your doctor about whether any of the drugs you take might make your memory worse.

Antipsychotic drugs can cause severe confusion, severe parkinsonism, sedation and sometimes death. Very rarely, certain second-generation antipsychotics, such as quetiapine (Seroquel) or clozapine (Clozaril, Versacloz) might be prescribed for a short time at a low dose but only if the benefits outweigh the risks.

Therapies

Because antipsychotic drugs can worsen Lewy body dementia symptoms, it might be helpful to first try nondrug approaches, such as:

• Tolerating the behavior. Some people with Lewy body dementia aren't distressed by the hallucinations. In these cases, the side effects of medication might be worse than the hallucinations themselves.
• Modifying the environment. Reducing clutter and noise can make it easier for someone with dementia to function. Caregivers' responses sometimes worsen behavior. Avoid correcting and quizzing a person with dementia. Offer reassurance and validation of his or her concerns.
• Creating daily routines and keeping tasks simple. Break tasks into easier steps and focus on successes, not failures. Structure and routine during the day can be less confusing.

Symptoms and progression are different for everyone with Lewy body dementia. Caregivers and care partners may need to adapt the following tips to individual situations:

• Speak clearly and simply. Maintain eye contact and 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.
• Encourage exercise. Benefits of exercise include improvements in physical function, behavior and depression. Some research shows exercise might slow cognitive decline in people with dementia.
• Provide mind stimulation. Participating in games, crossword puzzles and other activities that involve thinking skills might help slow mental decline in people with dementia. Encourage artistic and creative activities, such as painting, singing or making music.
• Create opportunities for social activity. Talk to friends. Participate in religious services.
• Establish bedtime rituals. Behavior issues can worsen at night. Create calming bedtime rituals without the distraction 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 daytime exercise might help prevent nighttime restlessness.

Frustration and anxiety can worsen dementia symptoms. To promote relaxation, consider:

• Music therapy, which involves listening to soothing music
• Pet therapy, which involves the use of animals to improve moods and behaviors in people with dementia
• Aromatherapy, which uses fragrant plant oils
• Massage therapy

People with Lewy body dementia often have a mixture of emotions, such as confusion, frustration, anger, fear, uncertainty, grief and depression. Offer support by listening, reassuring the person that he or she still can enjoy life, being positive, and doing your best to help the person retain dignity and self-respect.

If you're a caregiver or care partner for someone with Lewy body dementia, watch the person closely to make sure he or she doesn't fall, lose consciousness or react negatively to medications. Provide reassurance during times of confusion, delusions or hallucinations.

Looking after yourself

Caring for a person with Lewy body dementia can be exhausting physically and emotionally. You may have anger, guilt, frustration, discouragement, worry, grief or social isolation. Help prevent caregiver burnout by:

• Asking friends or other family members for help when you need it. Consider in-home health services to help you care for the person with Lewy body dementia.
• Exercising regularly and eating a healthy diet.
• Learning about the disease. Ask questions of doctors, social workers and others on the care team.
• Joining 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, referrals, home care agencies, supervised living facilities, a telephone help line and educational seminars.

You'll probably first discuss your symptoms with your family doctor, who may refer you to a doctor trained in dementia — usually a doctor trained in brain and nervous system conditions (neurologist) or mental health conditions (psychiatrist).

Ask a friend or family member to the appointment, if possible, to help you remember the information you're given and give your doctor information about you. Here's some information to help you get ready for your appointment.

What you can do

Make a list of:

• Your symptoms and when they began
• All medications, vitamins or other supplements you take, including doses
• Questions to ask your doctor

What to expect from your doctor

Your doctor is likely to ask you and your spouse, partner or close friend a number of questions about:

• Changes in your memory, personality and behavior
• Visual hallucinations
• Your history of stroke, depression, alcohol abuse, head trauma or other neurological disorders