Diagnosing Lewy body dementia can be difficult; symptoms are difficult to distinguish from those of Alzheimer's disease or Parkinson’s disease dementia.

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Lewy body dementia (also known as dementia with Lewy bodies, or DLB) affects up to 25 percent of individuals with progressive dementia in the United States, ranking second behind Alzheimer’s disease (AD). Yet most of us know little about this irreversible neurodegenerative disease.

Because early Lewy body dementia symptoms are difficult to distinguish from those of AD or Parkinson’s disease dementia (PDD, a related disorder involving problems with movement), diagnosis is difficult, and finding appropriate treatment can be challenging. Now two new studies have offered a glimmer of hope for patients with DLB and their families.

Lewy Body Dementia Causes and Risk Factors

DLB is associated with the formation inside the brain of abnormal microscopic accumulations of alpha-synuclein protein. These accumulations, Lewy bodies, form inside the nuclei of neurons in brain regions critical to memory and motor function, where they disrupt brain functioning.

It is not yet clear precisely what causes DLB. Research suggests that the risk for DLB may be higher in individuals who are 60 years of age or older, male, have a family history of DLB, or carry the genetic marker for dementia—the apolipoprotein E-4 variant (APOE4).

DLB patients are more likely to have a history of anxiety, depression and stroke. Compared to individuals with AD or Parkinson’s disease, people with DLB consume lower amounts of caffeine, which has been associated in several studies with certain neuroprotective effects.

Lewy Body Dementia Symptoms

Some symptoms—such as muscle rigidity and mental confusion—may initially resemble those of AD or Parkinson’s disease, a progressive movement disorder. There are subtle differences, however, and some of these differences become more apparent as the Lewy body dementia stages advance. Symptoms of DLB include:

• Dementia: People with DLB may have problems with recent memory, abstract thinking, planning, judgment, or problem-solving, although these problems may not be as extreme as those associated with PDD and AD.
• Movement symptoms: These may include muscle rigidity, a shuffling gait, and slowness of movement similar to, but often less severe than, symptoms associated with Parkinson’s disease. A person with DLB is less likely to have tremors, which are common in people with Parkinson’s disease.
• Behavioral problems: People with DLB often experience neuropsychiatric symptoms, such as visual and auditory hallucinations, paranoid delusions, and behavioral problems. These may occur early on in the disease process, rather than when the disease is greatly advanced, as in AD and PDD.
• Fluctuations in cognition: DLB is associated with unpredictable changes in alertness and concentration, and fluctuating periods of confusion. .
• Extreme sensitivity to antipsychotic medications: Antipsychotic drugs used to control behavioral symptoms in other types of dementia, such as haloperidol (Haldol) and thioridazine (Mellaril), can cause a marked worsening of movement disorders in people with DLB, and may lead to kidney failure or even death. .
• Sleep problems: Many individuals with DLB have REM sleep disorder, a condition in which people act out their dreams with violent movements while asleep. DLB may also be associated with excessive daytime drowsiness. .
• Other symptoms: People with DLB may be especially susceptible to falling, fainting spells, wide alterations in blood pressure, and depression. .

Originally published in May 2016 and updated.