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"Most people (with dementia) will get a diagnosis of Alzheimer's disease," Dr. Glenda Halliday says. "It is over-diagnosed."

Halliday, from Sydney's Prince of Wales Medical Research Institute, estimates 10 to 25 per cent of all dementia patients have abnormal protein deposits called Lewy bodies in certain areas of the brain.

Her autopsy studies of dementia patients show brain tissue is relatively undamaged when Lewy bodies are present. "And I think that's good news," Halliday says. "If you've got more brain, it's easier to fix."

She says she initially doubted her results. But as tests progressed on the brains of people who had died with dementia, she found those with the Lewy body proteins consistently had more brain cells remaining than their peers with Alzheimer's disease.

Many of these patients were wrongly diagnosed with Alzheimer's disease but responded better to drugs for the condition than those who actually had Alzheimer's.

This may be a factor contributing to wide individual variation in the effectiveness of such drugs, Halliday says.

Although her findings suggest people with Lewy body dementia benefit from Alzheimer's medication, she says it may well be possible to develop drugs more closely targeted to Lewy body disease.

Symptoms of Lewy body dementia include movement problems, confusion, loss of memory, hallucinations and delusions.

Vascular dementia is another common cause of thinking and language problems in the elderly. It results from reduced blood flow to the brain.

Source: The Medical Posting (online at www.medicalposting.ca)