Lewy body dementia

Lewy body dementia, the second most common type of progressive dementia after Alzheimer's disease, causes a progressive decline in mental abilities.

It may also cause visual hallucinations, which generally take the form of objects, people or animals that aren't there. This can lead to unusual behavior such as having conversations with deceased loved ones.

Another indicator of Lewy body dementia may be significant fluctuations in alertness and attention, which may include daytime drowsiness or periods of staring into space. And, like Parkinson's disease, Lewy body dementia can result in rigid muscles, slowed movement and tremors.

In Lewy body dementia, protein deposits, called Lewy bodies, develop in nerve cells in regions of your brain involved in thinking, memory and movement (motor control).

Symptoms Causes Risk factors Complications

Lewy body dementia signs and symptoms may include:

  • Visual hallucinations. You may see visual hallucinations, such as colors, shapes, animals or people that aren't there. Hallucinations may be one of the first symptoms of Lewy body dementia. Some people also may experience sound (auditory), smell (olfactory) or touch (tactile) hallucinations.
  • Movement disorders. You may experience symptoms similar to those of Parkinson's disease (parkinsonian symptoms), such as slowed movement, rigid muscles, tremors or a shuffling walk.
  • Poor regulations of body function. Blood pressure, pulse, sweating and digestive process are regulated by a part of the nervous system that is often affected by Lewy body dementia. This can result in dizziness, falls and bowel issues.
  • Cognitive problems. You may experience thinking (cognitive) problems similar to problems experienced in Alzheimer's disease, such as confusion, reduced attention span and eventually memory loss.
  • Sleep difficulties. You may have a sleep disorder called rapid eye movement (REM) sleep behavior disorder that can cause you to physically act out your dreams while you're asleep.
  • Fluctuating attention. You may have frequent episodes of drowsiness, long periods of staring into space, long naps during the day or disorganized speech.
  • Depression. You may experience depression sometime during the course of your illness.

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