Lewy body disease is the second most common brain degenerative disease after Alzheimer's disease. Lewy bodies, deposits of alpha-synuclein protein, are found in the brainstem, limbic system and cerebral cortex. Similar tissue changes are also seen in patients clinically diagnosed with Parkinson's disease.

Lewy body disease can be difficult to recognise at the beginning of the disease, as it progresses slowly. Symptoms often include movement disturbances, memory problems and psychiatric symptoms.

In their recent study, researchers from the Universities of Helsinki and Tampere investigated for the first time, the occurrence of Lewy body disease markers in young and middle-aged subjects who were not known to suffer from Lewy body or Parkinson's diseases. Previous similar studies have investigated the occurrence of the disease markers in people over 60 years old.

The researchers found that Lewy body disease changes may begin to develop in the brain already in middle age, even if there are no actual symptoms yet.

"Our findings indicate that Lewy body disease may be more common in people over 50 than previously thought. In the study, we found disease changes in nine percent of people over 50 who did not have a clinical diagnosis of Parkinson's disease or Lewy body disease. However, further studies are needed to confirm the results," says Associate Professor Liisa Myllykangas from the University of Helsinki.

Earlier diagnosis means more effective treatment

In their study, the researchers used internationally unique Finnish forensic autopsy data, which consists of approximately 600 people aged 16-95 who died outside hospitals.

Myllykangas says that in the future the treatments developed against degenerative brain diseases will be aimed at patients who are in the early stages of the disease, or are at risk of developing the disease.

"Finding out the prevalence of disease changes in younger age groups is therefore important as this will be the most effective time to start therapies," she comments.

The study has been published in the journal Annals of Neurology.