What is Lewy body dementia (LBD)?
Dementia Although less well known than Alzheimer’s and Parkinson’s diseases. Lewy body dementia (LBD) is not a rare disorder.
It is thought to be the second most common form of dementia, accounting for about 20% of all cases. Approximately 125,000 people in the United Kingdom suffer from its disabling symptoms. Taking into account families and/or other carers who have to deal with the disease, it probably affects the lives of at least half a million people.
LBD is caused by abnormal deposits of the protein alpha-synuclein in the brain which are associated with cell death. These deposits are called Lewy bodies, after Dr Friederich Lewy, who discovered them in 1912.
It differs from Alzheimer’s in that it affects not only cognitive abilities but motor skills (parkinsonisms) as well. In addition, people with LBD suffer from vivid visual hallucinations and dramatic fluctuations in consciousness, going from lucid to confused or barely conscious, sometimes from hour to hour.
Also unlike Alzheimer’s, impaired executive function rather than memory problems are the major and presenting cognitive symptoms. Executive function includes : performing complex mental activities such as multi-tasking, problem solving ,spatial awareness and analytical thinking.
There are two types of LBD: dementia with Lewy bodies (DLB) and Parkinson’s disease dementia (PDD). The difference between them is the timing of the onset of symptoms. Early Parkinson’s disease is characterised as a movement disorder whereas DLB initially presents as cognitive impairment. When cognitive symptoms precede motor symptoms by at least one year, it is considered to be DLB. In PDD the cognitive symptoms develop more than a year after the onset of motor problems. Over time, people with DLB or PDD develop similar symptoms.
DLB typically begins at the age of 50 or older, although sometimes younger people develop it. It appears to affect slightly more men than women. It is a progressive disease, which lasts an average of 5-7 years from the time of diagnosis to death but the time span can range from 2-20 years. How quickly the disease progresses varies from person to person, depending on overall health, age and severity of symptoms.
In the early stages usually before a diagnosis is made, symptoms can be mild and people can function fairly normally. But as the disease advances people with LBD require increasing amounts of help as their thinking and movement abilities decline. In the late stage of the disease they may depend entirely on others for assistance and care and be bedridden.
Early and accurate diagnosis is essential to ensure that people are not given the wrong medication. Drugs to alleviate motor symptoms can worsen hallucinations and certain antipsychotics can be fatal.
Research has improved understanding of this challenging condition and advances in science hopefully will lead to better diagnosis, improved care new treatment and eventually a cure.
More detailed and downloadable information can be found at www.lewybody.org