Lewy Body Dementia Symptoms and Causes

Lewy body dementia (LBD) is a disease related to Parkinson's disease and the second most common type of dementia after Alzheimer's disease. LBD is a progressive disease caused by abnormal protein deposits in the brain called Lewy bodies. Unlike Alzheimer's, LBD does not always cause memory loss until the disease is advanced.

The cause of LBD is unknown. While there are no drugs able to cure the disease, one approved by the U.S. Food and Drug Administration (FDA) may improve symptoms and increase survival. On average, people with LBD survive five to seven years after their diagnosis, but some live for far longer.

This article describes the signs and causes of Lewy body dementia, including how this progressive neurocognitive disorder is diagnosed and treated. It also explains the likely outcome for someone diagnosed with LBD.

What Are the Signs of Lewy Body Dementia?

Lewy body dementia usually causes a decline in thinking, visuospatial ability, information processing, perception, speaking, finding words, and recognizing things. Problems with memory are less common and tend only to occur later in the disease.

People with LBD commonly experience:

• Symptoms of Parkinsonism, including movement problems, stooped posture, frequent falls, and a lack of facial expression
• Drowsiness with fluctuating bursts of energy and alertness
• Recurrent visual hallucinations, especially of people and animals
• REM sleep behavior disorder, in which a person may act out their vivid dreams
• Mood symptoms, including depression and delusions
  
• Changes in autonomic (automatic) body functions, such as blood pressure, body temperature, and bladder or bowel control

LBD tends to be rapidly progressive, making it harder and harder to care for yourself within the first year of symptom appearance.

What Causes Lewy Body Dementia?

Scientists remain unclear as to the cause of Lewy body dementia. Genetics may play a part, but only 30% of people with DLB have a history of the disease in their family.

Because there is an overlap in gene mutations associated with LBD, Alzheimer's, and Parkinson's dementia, certain genes are thought to play a role in the disease. Chief among these is the apolipoprotein (APOE) gene which produces a protein that may regulate certain brain functions.

Further research is needed.

How Is Lewy Body Dementia Diagnosed?

Lewy body dementia is diagnosed based on clinical signs and symptoms of the disease as well as a review of your medical history and a detailed battery of cognitive tests.

There are currently no tests that can definitively diagnose LBD, not even brain scans or tissue biopsies. In the end, LBD can only be definitively after death with a brain autopsy. Until then, the diagnosis is considered presumptive rather than definitive.

A complete diagnostic workup is usually performed to rule out other possible causes of the symptoms. This may include a magnetic resonance imaging (MRI) or computed tomography (CT) scan of the brain, which can identify a stroke or brain tumor that can also cause cognitive and behavioral changes.

Blood tests may be used to rule out conditions like a severe infection, which can cause behavioral changes, especially with advanced age.

How Is Lewy Body Dementia Treated?

There is currently no cure for Lewy body dementia, but there are several medications that can help with symptom management. 

Among them, Exelon (rivastigmine) is the only drug currently approved by the FDA to treat LBD. Studies have shown that Exelon is not only able to improve cognition but may also increase survival. Available in capsule form, the drug is taken twice daily in doses ranging from 3 to 6 milligrams (mg).

Other drugs of the same class are also sometimes used off-label to treat LBD, including Aricept (donepezil) and Razadyne (galantamine).

Because people with LBD often have Parkinson-like symptoms, medications used to treat Parkinson's like levodopa may help ease tremors. However, these drugs can cause confusion and hallucinations, so they are used carefully under the direction of a healthcare provider.

Antidepressants like selective serotonin reuptake inhibitors (SSRIs) can be used to treat the depression associated with Lewy body dementia.

Non-drug strategies, like physical therapy and speech therapy, may be useful for managing functional symptoms of LBD. Simple strategies, like reducing caffeine intake and practicing relaxation before bedtime, may improve sleep patterns and decrease disruptive outbursts. 

What Is the Life Expectancy of a Person With Lewy Body Dementia?

The prognosis of someone with Lewy body dementia depends on multiple factors, including age at onset and overall health. On average, life expectancy with LBD is five to seven years, although the range is known to be between two and 20 years.

Because one of its characteristics is that its symptoms can fluctuate, progression in Lewy body dementia may vary significantly from one person to another.  

Summary

Lewy body dementia is a form of dementia caused by the deposit of an abnormal protein, called Lewy bodies, in the brain. Symptoms include the progressive loss of cognitive function, Parkinson-like tremors, and hallucinations. There is no cure for LBD, but certain drugs like Exelon (rivastigmine) may decrease symptoms and increase life expectancy.

People with LBD typically survive five to seven years after their diagnosis, but some live for up to 20 years.