Lewy body dementia was discovered at the end of the 1980s. Researchers found small accumulations of protein in samples of brain tissue taken post-mortem from patients with dementia. These accumulations were not a new discovery: they are called Lewy bodies and also occur in Parkinson’s disease.
What was new was that the Lewy bodies were found in other parts of the brain – in nerve cells spread throughout both the cortex and the brain stem – and in patients with dementia. By closely studying the records, it could be seen that the symptoms of the dementia patients who had been examined post-mortem differed a great deal from those symptoms typical of Alzheimer’s disease.
Lewy body dementia is now a diagnosis. It is estimated that it accounts for 2–20 per cent of all cases of dementia. It is probably seriously underdiagnosed, i.e. many people have the disease without having been diagnosed as such.
Typical features of Lewy body dementia are visual hallucinations and an impaired level of attention accompanied by marked fatigue. The symptoms can vary from mild to severe on the same day. Memory disturbances occur, particularly later on in the disease. However, they are less pronounced than in the case of Alzheimer’s disease. The patients are often well-oriented but have difficulty judging distances and perceiving objects in a three-dimensional way.
The disease often starts with disturbed dream sleep, where the person cries out and “fights” when dreaming – several years before other symptoms emerge.
Other characteristics of Lewy body dementia are stiffening of the muscles (rigidity) and slow, shuffling movements (hypokinesia). Such motor symptoms are also typical of Parkinson’s disease, but there they are generally more pronounced. Another difference is that, in Lewy body dementia, the motor symptoms appear at around the same time as the cognitive ones (problems with attention, memory, etc.)
Lewy body dementia leads to a gradual deterioration in motor function and cognitive capacity. There is no cure for the disease. The dementia symptoms can be alleviated in the early stages, when many people with Lewy body dementia respond well to treatment with so-called cholinesterase inhibitors (an Alzheimer’s medication). Low doses of L-dopa – a medication used in Parkinson’s disease – can be used if the motor symptoms become too troublesome.
Neuroleptics should be avoided as Lewy body dementia leads to a significant increase in sensitivity to such medications (which are used, among other things, to treat hallucinations).
Some of the following symptoms may occur with Lewy body dementia: hallucinations, confusion, sleep and pain. For more information about various symptoms click here.