Lewy Body Dementia: Symptoms and Diagnosis

June 27, 2019
Lewy body dementia is the third most common type of dementia. It’s devastating for both for the patient and their family. Read more about it here!

Lewy body dementia (LBD) is a brain degenerative syndrome. It’s caused by the formation of protein deposits that clump up in the brain areas of thought, memory, and motor skills.

It’s the second most common type of dementia after Alzheimer’s. Lewy body dementia shares many of Alzheimer’s and Parkinson’s disease symptoms, so it can be difficult to make an exact diagnosis. It has Alzheimer’s behavioral and cognitive symptoms and Parkinson’s muscle rigidity, slowness of movement, and tremors. However, people with LBD tend to also have very vivid visual hallucinations.

In this article, we’ll discuss the symptoms, how doctors diagnose it, and the causes.

A worried old man.

Lewy Body Dementia Symptoms

Lewy body dementia affects the brain progressively. The average life expectancy after diagnosis is about eight years. In the beginning, the usual symptoms resemble those of Parkinson’s disease, but as it evolves, other symptoms manifest. Several studies have found that the most common LBD symptoms are:

  • Vivid visual hallucinations. In general, hallucinations are recurrent and can take any shape, including animals or people who aren’t there. It’s also possible for patients to have other types of hallucinations, such as auditory, olfactory, or tactile.
  • Motor alterations. They’re very similar to those of Parkinson’s disease, including slowness of movement, muscle rigidity, tremors, and inability to walk properly.
  • Behavioral and cognitive disorders. Such as confusion, trouble focusing, time and space perception problems, and difficulty reasoning and deciding. All these symptoms are very similar to those of Alzheimer’s disease but are usually less severe.
  • Behavioral and cognitive disorder fluctuations. People who suffer from dementia can get better or worse overnight. For example, the patient could be able to talk and remember anything one day and be unable to the next.
  • Deficit in body function regulation. In general, LBD affects one part of the autonomic nervous system that’s specifically in charge of regulating blood pressure, perspiration, and digestion. Thus, the patient might feel dizzy or have bowel issues.

As we mentioned above, Lewy body dementia unravels progressively, so the symptoms tend to worsen in the last years of the patient’s life. This type of dementia can cause great suffering: the patient may fall into depression, become aggressive, and may suffer from more motor alterations.

Lewy Body Dementia Diagnosis

Lewy body dementia is hard to diagnose, mainly because it resembles other types of dementia, such as Alzheimer’s and Parkinson’s disease. Also, there’s no specific test to diagnose it. In fact, the patient must be subjected to a variety of tests to rule out other possible diseases.

How fast the symptoms start to develop is one of the most reliable indicators of LBD. If mental symptoms manifest in one year, the patient is most likely suffering from LBD. Then, following differential diagnosis, blood tests can demonstrate whether the symptoms are the result of a B12 vitamin deficiency, thyroid problems, or diseases such as syphilis and AIDS.

By exploring the brain with an MRI or a tomography, other conditions such as strokes, hydrocephalus, or a tumor can be ruled out. These images can be useful to diagnose LBD because the patients’ brains suffer very distinctive changes, such as cerebral atrophy and midbrain neurons death, especially in the substantia nigra.

Furthermore, the brain of LBD patients may have lesions, called Lewy neurites, that affect neuronal functioning. The most affected neurons are those of the hippocampus.

An old man and her wife with Lewy body dementia.

Causes and Risk Factors

Lewy body dementia is the result of an abnormal protein accumulation in the brain, which prevents normal cell communication and impairs neural regeneration. Its exact cause isn’t yet known.

However, studies revealed certain factors that increase the risk of contracting LBD. For example, it’s more common in men over the age of 60. Also, a person’s risk increases if a relative has suffered from LBD or Parkinson’s disease.