In addition to Alzheimer’s disease and vascular dementia, another one of the most common types of dementia is Dementia with Lewy bodies (DLB). Lewy bodies are abnormal, balloon-like structures made up of a certain type of protein. They form inside nerve cells and were first discovered by German neurologist Dr. Friederich Lewy in 1912. Why they form is not yet understood. Dementia with Lewy bodies is related to Parkinson’s disease dementia, so both will be discussed in this article.
Dementia with Lewy bodies is often difficult to diagnose because its symptoms can mimic Alzheimer’s disease and Parkinson’s disease when it occurs alone, but it also can co-exist with these two diseases. Symptoms similar to Alzheimer’s disease include memory loss, confusion, and poor judgment. Symptoms similar to Parkinson’s disease include changes in movement and posture, and difficulty with alertness and attention. Sometimes certain symptoms such as difficulty sleeping, loss of smell, and visual hallucinations may occur years before other more classic symptoms develop, leading to a misdiagnosis until the disease enters its later stages. When Dementia with Lewy bodies is present, cognitive symptoms usually occur within one year of symptoms involving movement and posture change. When Parkinson’s disease dementia occurs, the cognitive symptoms usually don’t develop until more than one year after the movement changes manifest themselves. While not everyone who is diagnosed with Parkinson’s disease will develop dementia, those who are diagnosed with Parkinson’s disease late in life are more likely to develop Parkinson’s disease dementia.
Not everyone with DLB will experience all of its symptoms. In addition to symptoms of altered thinking ability, unpredictable fluctuations in cognitive functioning (concentration, attention, and alertness) can occur, such as staring into space for periods of time or a several hour nap during the day despite a full night’s sleep. Visual hallucinations are common, auditory hallucinations occasionally happen. Movement symptoms can include changes in handwriting, muscle rigidity or stiffness, a shuffling or awkward gait, tremors (usually in the hands while at rest), stooped posture, trouble with balance or unexplained falls, decreased facial expressions, and difficulty swallowing or a weak voice. Sleep disorders are common, including REM sleep behavior disorder in which the person seems to act out dreams and speaks, has violent movements, or falls out of bed. Mood and behavior changes may also accompany DLB, and patients may demonstrate extreme sensitivity to antipsychotic medications used to treat these symptoms.
DLB usually begins in people over age 50 and, like Alzheimer’s disease, symptoms start slowly and lead to increasing deterioration in cognitive and physical functioning. A brain autopsy after death is the only method of definitively diagnosing this condition, and researchers currently are studying ways to more accurately diagnose it in the living brain. At the present time there is no cure or method of slowing the progression of DLB. Treatment focuses on controlling the symptoms. A neurologist who specializes in dementia and movement disorders can provide guidance and assistance for those who are affected by the symptoms of Dementia with Lewy bodies.
Karen Kaslow, RN