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Related Dementias

Diagnoses of Lewy Body Dementia

Lewy body dementia (LBD) refers to either of two related diagnoses—dementia with Lewy bodies and Parkinson's disease dementia. Both diagnoses have the same underlying changes in the brain and, over time, people with either diagnosis develop similar symptoms. The difference lies largely in the timing of cognitive (thinking) and movement symptoms. In dementia with Lewy bodies, cognitive symptoms develop within a year of parkinsonism—any condition that involves the types of movement changes, such as tremor or muscle stiffness, seen in Parkinson's disease. In Parkinson's disease dementia, cognitive symptoms develop more than a year after the onset of movement symptoms.Older woman with daughter behind her shoulder

Dementia with Lewy Bodies

People with dementia with Lewy bodies have a decline in thinking ability that may look somewhat like Alzheimer's disease. But over time they also develop movement and other distinctive symptoms that suggest dementia with Lewy bodies.

Symptoms that distinguish this form of dementia from others may include:

  • Visual hallucinations early in the course of dementia
  • Fluctuations in cognitive ability, attention, and alertness
  • Slowness of movement, tremor, difficulty walking, or rigidity (parkinsonism)
  • REM sleep behavior disorder, in which people physically act out their dreams by yelling, flailing, punching bed partners, and falling out of bed
  • More trouble with mental activities such as multitasking and problem solving than with memory early in the course of the disease

Parkinson's Disease Dementia

Parkinson's disease dementia starts as a movement disorder, with symptoms such as slowed movement, muscle stiffness, tremor, and a shuffling walk. These symptoms are consistent with a diagnosis of Parkinson's disease. Later on, cognitive symptoms of dementia and changes in mood and behavior may arise.

Not all people with Parkinson's disease develop dementia, and it is difficult to predict who will. Many older people with Parkinson's develop some degree of dementia.

For More Information About Types of LBD

NIA Alzheimer’s and related Dementias Education and Referral (ADEAR) Center
1-800-438-4380 (toll-free)
adear@nia.nih.gov
www.nia.nih.gov/alzheimers
The National Institute on Aging’s ADEAR Center offers information and free print publications about Alzheimer’s disease and related dementias for families, caregivers, and health professionals. ADEAR Center staff answer telephone, email, and written requests and make referrals to local and national resources.

Lewy Body Dementia Association
1-404-975-2322
1-844-311-0587 (toll-free LBD Caregiver Link)
www.lbda.org