Lewy Body Disease (or Dementia with Lewy Bodies - DLB) is sometimes misdiagnosed as Alzheimer's disease. This article describes DLB and highlights its unique features.

What is Dementia with Lewy bodies?

This disease is otherwise called Dementia with Lewy bodies (DLB), Lewy Body Dementia, and senile dementia of the Lewy body type. It has some signs and symptoms of both Alzheimer's and Parkinson's disease. The condition may account for 10 to 15 per cent of all cases of dementia in older people.

It takes its name from the doctor who first identified Lewy bodies, in 1912. Lewy bodies are tiny, spherical protein deposits that appear in nerve cells. Their presence in the brain affects the brain's normal functioning, and interferes with the action of essential chemical messengers, especially acetylcholine and dopamine.

These deposits have been identified in the brains of people with Parkinson's disease (PD). Some individuals who are initially diagnosed with PD later develop a dementia that resembles Lewy body disease.

Researchers do not fully understand why Lewy bodies occur in the brain.

Symptoms

Lewy body disease progresses at a similar rate as Alzheimer's disease, over several years.

People with Lewy body disease can experience the memory loss, spatial disorientation and communication difficulties associated with Alzheimer's disease.

They may also develop the main symptoms indicative of Parkinson's disease. These are: slowness, muscle stiffness, 'freezing' when attempting to start a movement, trembling of the limbs, a tendency to shuffle when walking, loss of facial expression, and loss of volume and tone of the voice, producing monotonous speech.

People with Lewy body disease may discover that their abilities fluctuate - daily, or even hourly.

They tend to fall, feel faint or have 'funny turns'. Visual hallucinations may occur.

While falling asleep during the day may be common, night times may be disturbed, sometimes with nightmares and confusion.

As the disease progresses, the early symptoms worsen. Memory loss may cause more problems and language skills deteriorate. Anxiety and depression may occur.

Men and women are affected in equal numbers. It is more common in people over the age of 65, as is the case with most types of dementia.

Diagnosis

It is difficult to diagnose. An accurate diagnosis of Lewy body disease is very important where the condition is suspected, as patients may react badly to strong tranquillizers (neuroleptics). For those with Lewy body disease, neuroleptics can be dangerous as they can induce Parkinson-like side effects such as rigidity, immobility and difficulty in communicating or performing certain tasks. There is also a slight risk of sudden death.

Doctors recommend that it is preferable to find ways of dealing with an individual's distress that do not involve medication and that neuroleptics should never be a substitute for high quality care.

Is there a cure?

There is currently no cure for Lewy body disease.

Troublesome symptoms such as hallucinations may respond to being challenged in a caring way, but it can sometimes be unhelpful to try to convince the person that the perceived vision does not exist. It is often better to try to provide reassurance and other distractions.

Those who experience rigidity and stiffness due to Parkinson-type symptoms may benefit from anti-Parkinson's disease drugs, although these may make hallucinations and confusion worse.

When caring for someone with Lewy body disease, flexibility is essential, bearing in mind that the symptoms often fluctuate.