Lewy body dementia or Lewy body disease is a much less common cause of cognitive problems and is seen in about seven in a thousand people over the age of 65. People with LBD tend to have trouble with visual spatial function and executive function. Executive function involves the ability to carry out complex tasks that have multiple steps, such as baking a cake. Early in the course of the disease, persons with LBD often have a fairly good memory. For example, remembering a list of words told to them five minutes before.
People with LBD may also have hallucinations or delusions. They may see people who are not present or have false beliefs such as thinking their house belongs to someone else. They often fluctuate in their degree of cognitive problems, having some days when they seem to do very well and others when they really struggle.
On a physical exam, the doctor may see some features similar to Parkinson’s disease such as slowed walking, smaller movements and handwriting, and stiffness. It is also common that people with LBD have a history of a disorder of sleep called REM sleep behavior disorder, or RBD. RBD often starts many years before cognitive problems develop. In RBD, people act out their dreams (which occur during REM sleep) and can injure themselves and their bed partner.
Unfortunately, there are not perfect treatments for LBD. But medications called cholinesterase inhibitors can help some patients. Rivastigmine is the one that has been studied the most extensively. Memantine is a different type of medication that may help some patients as well.
One of the most important things to be aware of is that people with LBD can respond very poorly to many typical antipsychotic medications, such as haloperidol and chlorpromazine. These medications are often used to treat delusions and are also given frequently for agitation. The typical ones should be avoided in LBD. There are two antipsychotics — quetiapine and clozapine — that can be used if delusions and hallucinations are problematic. If the parkinsonian features are prominent, a medication used to treat Parkinson’s disease, levodopa, may also be tried.
People with cognitive problems as well as RBD or hallucinations may have Lewy body dementia — not Alzheimer’s Disease. In this type of dementia, a neurological consultation is often particularly helpful.