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Symptoms and Signs of Lewy Bodies Dementia (LBD)

Doctor's Notes on Dementia with Lewy Bodies

Lewy body dementia (LBD) is a syndrome that describes dementia associated with or possibly caused by small clumps of proteins abnormally aggregate inside nerve cells in the brain. Signs and symptoms are early cognitive impairment like loss of recent memory and difficulty thinking and behavioral disturbances like depression, delusions, hallucinations but not motor symptoms like tremors or foot schuffling as is the case for Parkinson’s disease. However, motor symptoms can appear later as the disease progresses. Signs and symptoms slowly progress over time; finding Lewy bodies in brain cells at autopsy is the only confirmation of Lewy bodies in brain cells.

The cause of Lewy body dementia and even the cause of Lewy body formation is unknown. Some researchers suggest Lewy bodies aggregate and eventually damage and kill the brain cell they inhabit while others suggest Lewy body formation is a symptom of an unknown toxic event in the brain cell.

Medical Author:
Medically Reviewed on 3/11/2019

Dementia with Lewy Bodies Symptoms

Symptoms vary from person to person with dementia with Lewy bodies. The one characteristic common to everyone with dementia with Lewy bodies is progressive loss of mental abilities that interferes with everyday activities. This may include the following:

  • Loss of recent memory
  • Inability to concentrate or pay attention
  • Difficulty thinking, reasoning, solving problems
  • Misperceptions of space and time

Mental function usually varies in dementia with Lewy bodies, getting better and worse over time. Although the sharpness of our mental function varies in everyone - we all have our good moments and bad moments, or are "morning" persons or "evening" persons - this fluctuation is especially dramatic in dementia with Lewy bodies. This is especially true of alertness and attention. A person with dementia with Lewy bodies typically has periods of being alert, coherent, and oriented that alternate with periods of being confused and less responsive. This usually is considered more characteristic of dementia with Lewy bodies than of other types of dementia. Other symptoms include the following:

  • Abnormal movements of Parkinson's disease (shuffling gait, tremor, muscle stiffness)
  • Visual hallucinations
  • Depression
  • Nonvisual hallucinations (hearing, smell, touch)
  • Delusions
  • Agitation
  • Unexplained fainting
  • Sensitivity to "neuroleptic" drugs given to control hallucinations and delusions

None of these symptoms are unique to dementia with Lewy bodies or definitively point to dementia with Lewy bodies as a diagnosis. In fact, people with dementia with Lewy bodies often are very difficult to distinguish from those with Alzheimer's disease. People with dementia with Lewy bodies, however, often develop both Alzheimer's symptoms and Parkinson's symptoms within 1 year of each other.

Dementia with Lewy Bodies Causes

We do not know why Lewy bodies form in the brain.

Dementia, Alzheimer's Disease, and Aging Brains Slideshow

Dementia, Alzheimer's Disease, and Aging Brains Slideshow

In 1906 Auguste Deter, a woman in her early 50s, became the first person diagnosed with Alzheimer's disease, a form of dementia. The disease is named after the doctor who first described it, Alois Alzheimer. The disease is characterized by odd behavior, memory problems, paranoia, disorientation, agitation, and delusions. After Deter’s death, Alzheimer performed a brain autopsy and discovered dramatic shrinkage and abnormal deposits in and around nerve cells.

In 1910 the term “Alzheimer’s Disease” was formally used. In 1974 Congress established the National Institute on Aging (NIA), the primary federal agency supporting Alzheimer’s research.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.