What is dementia with lewy bodies (DLB)?

Dementia with Lewy bodies (DLB) is a form of dementia. Dementia refers to a range of brain diseases associated with memory loss and a decline in thinking skills that impact a person's ability to perform everyday activities and eventually care for oneself. DLB is closely associated with
Parkinson's disease
, a neurological disease that affects the nervous system and causes a person's muscles to tremor and shake.

According to the Alzheimer's Association, DLB is the third most common form of dementia and affects more than one million Americans. Alzheimer's disease is the most common type of dementia and affects 60 to 80 percent of all cases. Vascular dementia is the second most common form. Each type of dementia presents similar symptoms with minor differences, which makes diagnosis difficult.

What Are Lewy Bodies?

Lewy bodies are clumps of alpha-synuclein proteins found in nerve cells in areas of the brain that control memory and motor skills. They were named for Frederick H. Lewy, the neurologist who discovered them during the early twentieth century. Lewy bodies are the cause of DLB and Parkinson's disease. They also are found in the brains of people diagnosed with Alzheimer's disease and other forms of dementia such as Parkinson's disease dementia. Because these diseases share many of the same symptoms, doctors sometimes have difficulty definitively diagnosing DLB.

Researchers do not know much about Lewy bodies. They do not know why they appear in the brain or how they cause abnormalities. However, they have linked the formation of Lewy bodies to low levels of acetylcholine and dopamine in the brain as well as a connection loss between nerve cells. The presence of Lewy bodies in the brain causes nerve cells to die and a person to lose brain tissue.

Where the Lewy bodies are located in the brain affects which symptoms a person will experience. Those found at the base of the brain typically affect movement and cause motor problems. These are most common in patients with Parkinson's disease. Lewy bodies located in the outer layers of the brain affect mental capabilities and cause cognitive issues. These symptoms are found in patients with DLB. Some people with Lewy bodies experience both motor and cognitive problems. According to the Alzheimer's Society, nearly one-third of all patients with Parkinson's disease will eventually develop a form of dementia known as Parkinson's disease dementia. About two-thirds of people with DLB will develop motor problems.

Symptoms

Researchers have found that DLB affects men and women equally and is more common in those older than sixty-five, although it can affect younger individuals. Researchers have not established a clear family history of the disease.

Early symptoms of DLB may be easy to miss as many are not clearly noticeable at first. Symptoms of DLB may mimic those of both Alzheimer's and Parkinson's diseases. A person may also exhibit symptoms that are clearly associated with DLB, such as hallucinations.

As DLB progresses, symptoms will become more noticeable and severe and will eventually interfere with a person's ability to perform simple tasks and provide self care. Patients with later stages of DLB will need round-the-clock care. The life expectancy for a person diagnosed with DLB varies, however, the Alzheimer's Society estimates that a person with DLB might live for eight years after the onset of symptoms.

Following are symptoms of DLB:

• Alertness and attention problems (typically fluctuates throughout the day)




• Behavior issues (agitation, restlessness)




• Confusion




• 
  Delusions (believing things that are not true)




• 
  Depression
  




• Fainting or losing consciousness




• 
  Memory loss (especially regarding day-to-day events)




• Motor problems (slow movement, balance issues, shuffled walking, hunched posture, tremors—all usually associated with Parkinson's disease)




• Rapid eye movement (REM) sleep disorder (restless sleep in which a person violently acts out dreams)




• Speech issues




• Swallowing problems (could lead to choking)




• Thinking and reasoning changes




• Visual and auditory hallucinations (seeing things and/or hearing sounds that do not exist)




• Vision problems (especially the inability to judge distances or perceive objects)

Diagnosis

No test exists to help doctors diagnose DLB, which makes the disease difficult to determine. The only definitive way to diagnose DLB is with a postmortem autopsy. Because symptoms mimic those of other forms of dementia, sometimes doctors mistakenly diagnose people with DLB as having Alzheimer's disease.

After conducting a physical examination and blood tests, a doctor will talk to the patient (and sometimes a close family member) about the individual's medical history and known symptoms. Doctors are mostly able to diagnose DLB based on several predominant symptoms. These include movement problems, fluctuating attention or alertness, and hallucinations.

Once the presence of these symptoms has been established, doctors should perform additional examinations on the patient to test mental abilities and neurological functions. In addition, they should perform brain scans such as computed tomography (CT) or magnetic resonance imaging (MRI) scans to rule out any other conditions that could be causing symptoms. These scans are also helpful in diagnosing other forms of dementia such as vascular dementia.

Treatment

No cure exists for DLB. The disease can be managed through care and medication; however, the use of drugs will not stop or slow the progression of the disease. Medication may temporarily improve symptoms for an individual. The use of drugs is not always feasible because people with DLB may not be able to tolerate certain medications typically used to treat other forms of dementia. In addition, medication does not always work for all symptoms or may cause harmful side effects.

A doctor should treat the worst or most bothersome symptoms for a person with DLB. For example, a doctor may treat a DLB patient with antipsychotic drugs for hallucinations and delusions, antidepressants for depression, or sleep aids for REM sleep disorder.

Scientists are conducting studies and clinical trials to try to find a cure for all forms of dementia. The disease continues to devastate millions of people around the world. Many resources, including organizations and support groups, exist for those caring for people with DLB and other forms of dementia.

Bibliography

"Dementia with Lewy Bodies." Alzheimer's Association. Alzheimer's Association. Web. 14 Jan. 2015. http://www.alz.org/dementia/dementia-with-lewy-bodies-symptoms.asp

Firger, Jessica. "What Is Lewy Body Dementia?" CBS News. CBS Interactive Inc. 11 Nov. 2014. Web. 14 Jan. 2015. http://www.cbsnews.com/news/what-is-lewy-body-dementia/

"NINDS Dementia with Lewy Bodies Information Page." National Institute of Neurological Disorders and Stroke. National Institute of Neurological Disorders and Stroke. Web. 14 Jan. 2015. http://www.ninds.nih.gov/disorders/dementiawithlewybodies/dementiawithlewybodies.htm

"What Is Dementia?" Alzheimer's Association. Alzheimer's Association. Web. 14 Jan. 2015. http://www.alz.org/what-is-dementia.asp

"What Is Dementia with Lewy bodies (DLB)?" Alzheimer's Society. Alzheimer's Society. Web. 14 Jan. 2015. http://www.alzheimers.org.uk/site/scripts/documents_info.php?documentID=113