Lewy Body Dementia

What is Lewy body dementia (LBD)?

LBD is a progressive, neurodegenerative form of cognitive change. The hallmark of the disease is the presence of Lewy bodies, normal proteins that become abnormally clumped together inside neurons, or brain cells. They are named after Dr. Frederick Lewy, the neurologist who discovered them while working in Dr. Alois Alzheimer’s laboratory and who first described them in 1912. Dr. Lewy discovered Lewy bodies in the brains of people with Parkinson’s disease.

In people with LBD, Lewy bodies can be seen in various parts of the brain, including the brainstem and cortex. The neurotransmitter systems in the brain tend to be affected in LBD, which may be associated with the symptoms seen in these patients.

Although Lewy body dementia does not receive as much publicity or attention as Alzheimer’s disease or Parkinson’s, it is the third most common cause of dementia after Alzheimer’s and vascular dementia, accounting for 10 to 25 percent of cases, according to the Alzheimer’s Association.
What are the symptoms of LBD?

Individuals with LBD can have difficulty in any of the cognitive domains, especially memory, visuospatial skills, and attention-executive functioning (e.g., the ability to plan, to anticipate, to initiate an action, and to think abstractly). Other symptoms may include one or more of the following:

  • Parkinsonism, characterized by slowness of movement (bradykinesia), tremor, rigidity and shuffling of gait.
  • Visual hallucinations, which typically involve well-formed animals or people.
  • Fluctuations in attention and alertness during the day.

LBD also can be associated with sleep symptoms, such as acting out dreams at night (or dream enactment behavior). Some patients may have symptoms of autonomic dysfunction, such as constipation or orthostatic lightheadedness. Finally, psychiatric symptoms such as depression, anxiety or lack of motivation may be seen.

How it LBD diagnosed?

A physician will take a careful clinical history and physical examination. A laboratory workup may include thyroid studies, a complete metabolic panel, a complete blood count and vitamin levels to rule out another cause of cognitive problems. Imaging of the brain with an MRI or a CT usually does not show atrophy or shrinkage of the brain until later stages of the disease process. If there is a concern about an underlying sleep issue, such as dream enactment behavior, a sleep study may be ordered to determine whether the patient’s symptoms are being caused by a REM sleep behavior disorder.

What treatments exist?

There is no cure for LBD, and treatment is geared primarily toward treating symptoms. Acetylcholinesterase inhibitors such as donepezil may be considered if the patient is experiencing significant memory changes. Signs of parkinsonism can be treated with medications, such as levodopa-carbidopa. If a sleep study suggests that a REM sleep disorder may be causing dream enactment behavior, medications such as clonazepam and melatonin may be beneficial. Individuals who have underlying depression and/or anxiety may benefit from appropriate medications and a referral for psychotherapy.

How can I reduce my risk of LBD?

Studies have yet to reveal any method for reducing the risk of LBD. Adequate treatment of contributing factors, including underlying medical disorders, psychiatric conditions, and sleep issues, is essential. Exercise and other physical activity may be helpful, and patients are encouraged to remain socially and cognitively active. Because both cognitive changes and parkinsonism can increase the risk of falls in those with LBD, taking steps to reduce the risk of falling is vital.

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