Parkinsonism Occurs Frequently in Chronic Traumatic Encephalopathy

TUESDAY, July 16, 2024 (HealthDay News) -- Multiple substantia nigra (SN) pathologies are associated with parkinsonism, according to a study published online July 15 in JAMA Neurology.

Jason W. Adams, Ph.D., from the Boston University Alzheimer's Disease and CTE Center, and colleagues examined the frequency of parkinsonism in individuals with chronic traumatic encephalopathy (CTE) in a cross-sectional study.

The researchers found that parkinsonism occurred frequently in individuals with CTE, occurring in 24.7 percent of 481 male brain donors with neuropathologically diagnosed CTE. Compared with those without parkinsonism, those with parkinsonism had a more severe CTE stage (e.g., stage IV: 29.4 versus 10.8 percent) and nigral pathology (neurofibrillary tangles [NFTs]: 42.7 versus 29.9 percent; neuronal loss: 52.1 versus 17.1 percent; Lewy bodies [LBs]: 24.1 versus 5.8 percent). Associations were seen for years of contact sports participation with substantia nigra (SN) NFTs and neuronal loss. Associations were also seen for nigral neuronal loss and LBs with parkinsonism. SN neuronal loss was associated with SN LBs, SN NFTs, and arteriolosclerosis. A regression analysis demonstrated that SN NFTs and neuronal loss mediated the association between years of play and parkinsonism in the context of CTE among American football players.

"The findings suggest that extensive repetitive head injury is associated with parkinsonism through increased tau pathology and neuronal loss, even in the absence of Lewy pathology," the authors write.

Several authors disclosed ties to the biopharmaceutical and sports industries.

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