Parkinson's disease is classically associated with the buildup of proteins called Lewy bodies in brain cells, but researchers found that 76% of individuals with CTE and Parkinsonism did not have Lewy body pathology.
CTE is a degenerative brain disease whose only known cause is repetitive head impacts, like those encountered in contact sports. A 2018 study by the same research team found that duration of contact sports play is associated with and increased odds of developing Lewy body disease. However, the present study is the first to describe a link between contact sport participation, brainstem pathology, and parkinsonism in CTE.
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Substantia Nigra Pathology, Contact Sports Play, and Parkinsonism in Chronic Traumatic Encephalopathy
Key Points
Question What are the key clinical and neuropathologic measures associated with parkinsonism in individuals with chronic traumatic encephalopathy (CTE)?
Findings In this cross-sectional study of 481 brain donors with neuropathologically diagnosed CTE, parkinsonism was common (24.7%). Substantia nigra Lewy bodies, neurofibrillary tangles, dopaminergic neuronal loss, and age at death were significantly associated with parkinsonism.
Meaning The findings suggest that multiple abnormal protein accumulations and neuronal loss are associated with parkinsonism in individuals with CTE in an age-dependent manner.
Conclusions and Relevance In this cross-sectional study of contact sports athletes with CTE, years of contact sports participation were associated with SN tau pathology and neuronal loss, and these pathologies were associated with parkinsonism. Repetitive head impacts may incite neuropathologic processes that lead to symptoms of parkinsonism in individuals with CTE.
https://jamanetwork.com/journals/jamaneurology/article-abstract/2820667