Athletes who play contact sports associated with repetitive head impacts, such as football and ice hockey, may be at increased risk for Lewy body disease, which can cause Parkinson’s, a brain disorder that leads to impaired movement and thinking, according to a new study by researchers at the VA Boston Healthcare System, Boston University School of Medicine (MED), and Boston University School of Public Health.
The new findings, published in the Journal of Neuropathy and Experimental Neurology, come amid mounting evidence that repetitive head impacts from contact sports and other exposures are associated with the neurodegenerative disease chronic traumatic encephalopathy (CTE) and dementia.
Since CTE was first described in “punch drunk” boxers in the 1920s, scientists have hypothesized that the motor symptoms that appear in a minority of CTE cases, including tremors, slowness, and difficulty walking, were caused by CTE pathology.
But the new study suggests that those motor symptoms are instead caused by a separate disease, now also linked to contact sports participation, called Lewy body disease (LBD). LBD, which can lead to what is known as Lewy body dementia as well as Parkinson’s disease, is associated with problems with movement, cognition, depression, sleep, and visual hallucinations. This newfound relationship between contact sports and LBD appears to be independent of CTE pathology.
“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,” explained the study’s corresponding author, Dr. Thor Stein, a physician and neuropathologist at the VA Boston Healthcare System and assistant professor of pathology and laboratory medicine at MED.