Lewy Body Dementia

Lewy body dementia causes a decline in mental abilities that gradually gets worse over time. People with Lewy body dementia might see things that aren’t there. This is known as visual hallucinations. They may also have changes in alertness and attention.

People with Lewy body dementia might experience Parkinson’s disease symptoms. These symptoms may include rigid muscles, slow movement, trouble walking, and tremors.

Symptoms

• Visual hallucinations: Seeing things that aren’t there, known as hallucinations, might be one of the first symptoms of Lewy body dementia. This symptom often occurs regularly. People with Lewy body dementia might see shapes, animals, or people that aren’t there. Hallucinations involving sounds, smells, or touch are possible.
• Movement disorders: Signs of Parkinson’s disease, known as Parkinsonian signs, may occur. These symptoms include slowed movement, rigid muscles, tremor, or a shuffling walk. This can cause the person to fall.
• Poor regulation of body functions: The part of the nervous system that controls automatic functions is called the autonomic nervous system. Lewy body dementia can affect how well the autonomic nervous system controls blood pressure, heart rate, sweating, and digestion. This can result in sudden drops in blood pressure upon standing, dizziness, falls, loss of bladder control, and bowel issues such as constipation.
• Cognitive problems: People with Lewy body dementia might have thinking problems like those of Alzheimer’s disease. They may include confusion, poor attention, visual-spatial problems, and memory loss.
• Trouble with sleep: People with Lewy body dementia can have rapid eye movement (REM) sleep behaviour disorder. This disorder causes people to physically act out their dreams while asleep. People with REM sleep behaviour disorder may punch, kick, yell or scream while sleeping.
• Varying attention: Episodes of drowsiness, long periods of staring into space, long naps during the day or disorganised speech are possible.
• Depression: People with Lewy body dementia might develop depression.
• Apathy: Loss of motivation may occur.

Causes

Lewy body dementia is characterised by the 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.

Risk factors

• 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.

Complications

Lewy body dementia is progressive. This means it gradually gets worse over time. As symptoms get worse, Lewy body dementia can lead to:

• Severe dementia.
• Aggressive behaviour.
• Depression.
• Increased risk of falling and injury.
• Worsening of Parkinsonian symptoms, such as tremors.
• Death, on average, about 7 to 8 years after symptoms start.

Diagnosis

People who are diagnosed with Lewy body dementia have a gradual decline in their ability to think. They also have at least two of the following:

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

Other symptoms support a Lewy body dementia diagnosis. This includes problems with the autonomic nervous system. When this happens, the body can’t regulate blood pressure, heart rate, body temperature and sweating.

Sensitivity to medicines that treat psychosis also supports a diagnosis. This is particularly true for medicines such as haloperidol (Haldol). Antipsychotic medicines aren’t used for people with Lewy body dementia because they can make symptoms worse.

No single test can diagnose Lewy body dementia. The diagnosis is based on your symptoms and by ruling out other conditions. Tests might include:

Neurological and physical exam

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

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

Assessment of mental abilities

A short test, which assesses memory and thinking skills, can be done in less than 10 minutes. The test doesn’t usually distinguish between Lewy body dementia and Alzheimer’s disease. But the test can determine whether you have cognitive impairment. 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 tumour. Dementias are diagnosed based on the medical history and physical examination. But 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 symptoms aren’t typical, you may need other imaging tests. These imaging tests may support a diagnosis of Lewy body dementia:

• Fluorodeoxyglucose PET brain scans, which assess brain function.
• Single-photon emission computerised tomography (SPECT) or PET imaging. These tests can show reduced dopamine transporter uptake in the brain. This can help diagnose Lewy body dementia.

Sleep evaluation

You may need a sleep evaluation called a polysomnogram to check for REM sleep behaviour disorder. You may also need an autonomic function test to look for signs of heart rate and blood pressure instability.

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.

Treatment

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 medicines work by increasing the levels of chemical messengers in the brain, known as neurotransmitters. These chemical messengers are believed to be important for memory, thought and judgment. They include rivastigmine (Exelon), donepezil (Aricept, Adlarity) and galantamine (Razadyne ER). The medicines may help improve alertness and thinking. They may also reduce hallucinations and other behavioural symptoms. Possible side effects include stomach upset, muscle cramps and urinating more often. 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 medicines: Medicines such as carbidopa-levodopa (Sinemet, Duopa, others) can help reduce rigid muscles and slow movement. However, these medicines can also increase confusion, hallucinations and delusions.
• Medicines to treat other symptoms: Your doctor might prescribe medicines to treat other symptoms, such as sleep problems or movement problems.
• Certain medicines can worsen memory. Don’t take sleep aids that contain diphenhydramine. Also, don’t take medicines used to treat urinary urgency, such as oxybutynin (Ditropan XL, Gelnique, Oxytrol).
• Limit sedatives and sleeping medicines. Talk to a health care professional about whether any of the medicines you take might make your memory worse.
• Antipsychotic medicines 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 they’re offered only if the benefits outweigh the risks.

Therapies

Antipsychotic medicines can worsen Lewy body dementia symptoms. It might be helpful to first try other approaches, such as:

• Tolerating the behaviour: Some people with Lewy body dementia aren’t distressed by the hallucinations. If this is true, the side effects of the medicine 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 behaviour. 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.