Individuals who play contact sports such as football, ice hockey, and boxing, may be at increased risk for developing Lewy Body Disease, which can cause Parkinson's disease, finds a study.

The study showed that repetitive head impacts from contact sports and other exposures are associated with motor symptoms including tremors, slowness and difficulty walking and are caused by Lewy Body Disease. Lewy Body Disease which can lead to Parkinson's disease and Lewy Body Dementia, is also associated with problems with cognition, depression, sleep, and visual hallucinations.

"We found the number of years an individual was exposed to contact sports, including football, ice hockey, and boxing, was associated with the development of neocortical LBD, and LBD, in turn, was associated with Parkinsonism and dementia," said Thor Stein, neuropathologist at the Boston University.

The research team examined 694 brains. The total years of contact sports play was linked to an increased risk of having LBD in the cortex of the brain. Those who played more than eight years of contact sports had the greatest risk of LBD, which was six times higher than those who played eight years or less. Clinically, athletes with both chronic traumatic encephalopathy (CTE)-- a neurodegenerative disease -- and LBD were significantly more likely to have dementia and the symptoms of Parkinson's disease.