The following is a summary of “Relative contributions of mixed pathologies to cognitive and functional symptoms in brain donors exposed to repetitive head impacts,” published in the November 2023 issue of Neurology by Saltiel et al.
Researchers performed a retrospective study to investigate the relative contributions of 13 neuropathologies to cognitive symptoms and dementia in brain donors exposed to repetitive head impacts (RHI).
They examined brain tissue from 571 donors exposed to RHI and evaluated the presence of 13 neuropathologies, such as CTE, Alzheimer’s disease (AD), Lewy body disease (LBD), and TDP-43 inclusions. Cognitive status was evaluated based on dementia presence, the Functional Activities Questionnaire (FAQ), and the Cognitive Difficulties Scale (CDS). Spearman’s rho was computed to analyze the intercorrelation of these pathologies. Furthermore, they compared frequencies of pathological co-occurrence to a simulated distribution, assuming no intercorrelation. The relationship between neuropathologies, dementia status, and cognitive scores was analyzed using logistic and linear regressions.
The results showed that the sample’s age range was 18 to 97 years (with a median of 65.0 [IQR 46.0–76.0]). About 77.2% of donors displayed at least one moderate to severe neurodegenerative or cerebrovascular pathology. Stage III-IV CTE was the most prevalent neurodegenerative disease (43.1%), followed by TDP-43 pathology AD and hippocampal sclerosis. There were correlations between neuropathologies, with fewer unique combinations than expected if the pathologies were independent (P<0.001). The primary contributors to dementia were AD, neocortical LBD, hippocampal sclerosis, cerebral amyloid angiopathy (CAA), and CTE.
They concluded that multiple neuropathologies, including CTE, contribute to cognitive impairment in contact sport athletes exposed to RHI.