What is dementia with lewy bodies (dlb)?
What is dementia with
Lewy bodies (DLB)?
Dementia with Lewy bodies (DLB) is a form of dementia that shares characteristics with bothAlzheimer's and Parkinson's diseases. It accounts for around ten per cent of all cases of dementia inolder people and tends to be under-diagnosed. Dementia with Lewy bodies is sometimes referred toLewy body disease, cortical Lewy body disease and senile dementia of Lewy body type. All theseterms refer to the same disorder. This factsheet outlines the symptoms of DLB, how it is and how it is treated.
Dementia with Lewy bodies appears to affect men and women equally. As with all it is more prevalent in people over the age of 65. However, in certain rare cases people under 65 maydevelop DLB.
What are Lewy bodies?
Lewy bodies, named after the doctor who first identified them in 1912, are tiny, spherical proteindeposits found in nerve cells. Their presence in the brain disrupts the brain's normal functioning,interrupting the action of important chemical messengers, including acetylcholine and dopamine.
Researchers have yet to understand fully why Lewy bodies occur in the brain and how they causedamage.
Lewy bodies are also found in the brains of people with Parkinson's disease, a progressiveneurological disease that affects movement. Many people who are initially diagnosed with Parkinson'sdisease later go on to develop a dementia that closely resembles DLB.
What are the symptoms of dementia with Lewy bodies?
. This means that over time the symptoms willbecome worse. In general, DLB progresses at about the same rate as Alzheimer's disease, typicallyover several years.
They may experience problems with attention and alertness, often have spatial disorientation
and experience difficulty with 'executive function', which includes difficulty in planning aheadand co-ordinating mental activities. Although memory is often affected, it is typically less sothan in Alzheimer's disease.
They may also develop the symptoms of Parkinson's disease, including slowness, musclestiffness, trembling of the limbs, a tendency to shuffle when walking, loss of facial expression,and changes in the strength and tone of the voice.
There are also symptoms that are particular to dementia with Lewy bodies. In addition to thesymptoms above, a person with DLB may:
experience detailed and convincing visual hallucinations (seeing things that are not there),often of people or animals
find that their abilities fluctuate daily, or even hourly
fall asleep very easily by day, and have restless, disturbed nights with confusion, nightmaresand hallucinations
How is dementia with Lewy bodies diagnosed?
Dementia with Lewy bodies can be difficult to diagnose, and this should usually be done by aspecialist. People with DLB are often mistakenly diagnosed as having Alzheimer's disease or vasculardementia instead. The diagnosis of DLB is made on the basis of the symptoms - particularly persistentvisual hallucinations, fluctuation and the presence of the stiffness and trembling of Parkinson's. Newbrain-imaging tests can also help.
, but a proper diagnosis is particularlyimportant in cases of suspected DLB since people with DLB have been shown to react badly to certainforms of medication (see 'DLB and neuroleptics', below).
How is dementia with Lewy bodies treated?
At present, there is no cure for dementia with Lewy bodies. Symptoms such as maydiminish if challenged, but it can be unhelpful to try to convince the person that there is nothing there.
It is sometimes better to try to provide reassurance and alternative distractions. For more information,see Factsheet 520, .
Recent research suggests that the cholinesterase inhibitor drugs used to treat Alzheimer's diseasemay also be useful in treating DLB, although they are not yet licensed for this use. However, recentguidelines from the National Institute of Clinical Excellence (NICE) do suggest that these drugs shouldbe considered for 'people with DLB who have non-cognitive symptoms causing significant distress tothe individual, or leading to behaviour that challenges'.
A recent study also found the drug memantine (Ebixa) to improve general function in DLB althoughfurther studies are required to confirm this.
People who are experiencing symptoms such as rigidity and stiffness due to parkinsonism may benefitfrom anti-Parkinson's disease drugs, although these can make hallucinations and confusion worse.
Physiotherapy and mobility aids may also help alleviate these problems.
Dementia with Lewy bodies and neuroleptics
Neuroleptics are strong tranquillisers usually given to people with severe mental health problems. Inthe past, they have frequently been prescribed to people with dementia. However, it is alwayspreferable to find ways of dealing with a person's distress and disturbance that do not involvemedication. Under no circumstances should neuroleptics be prescribed as a substitute for good qualitycare.
For people with dementia with Lewy bodies, neuroleptics may be particularly dangerous. This class ofdrugs induce Parkinson-like side-effects, including rigidity, immobility, and an inability to perform tasksor to communicate. Studies have shown that they may even cause sudden death in people with DLB.
If a person with DLB must be prescribed a neuroleptic, this should be done with the utmost care,under constant supervision, and should be monitored regularly.
The names of many of the major neuroleptics available are listed below. New drugs are appearingfrom time to time. The generic name is given first, followed by some of the common proprietary (drugcompany) names for that particular compound: aripiprazole (Abilify), chlorpromazine (Largactil),clopenthixol (Clopixol), haloperidol (Haldol, Serenace), olanzapine (Zyprexa), promazine quetiapine(Seroquel), risperidone (Risperdal), sulpiride (Dolmatil, Sulparex, Sulpitil), trifluoperazine (Stelazine).
When caring for someone with dementia with Lewy bodies, it is important to be as flexible as possible,bearing in mind that the symptoms of DLB will fluctuate.
For details of Alzheimer's Society services in your area, visit
Last updated: September 2010Last reviewed: September 2010
Written and reviewed by: Professor Ian McKeith, Professor of Old Age Psychiatry, Institute for Ageingand Health, Newcastle University
Alzheimer's Society National Dementia Helpline
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