Chronic traumatic encephalopathy – neuropathology in athletes and war veterans

Abstract

Objective: The neuropathologic findings of chronic traumatic encephalopathy (CTE) were first described almost 40 years after the first clinical reports. We reviewed the literature and describe the neuropathological findings seen primarily in professional athletes and more recently, in war veterans. Methods: We reviewed the literature of CTE concentrating on references that focused on the correlation of clinical findings with the neuropathologic changes. The pathobiology and proposed mechanisms of injury are described. Diagnostic modalities and various diagnostic criteria of CTE are reviewed. Results: We are beginning to understand the neuropathologic basis of CTE, which appears to be a consequence of repetitive mild brain injuries. There appear to be reproducible criteria for the post-mortem diagnosis of CTE and the neuropathologic findings are becoming more widely accepted. More research is required to elucidate the risk factors that predispose athletes and war veterans to CTE. There is also a need for more diagnostic markers and a method to assess CTE in patients prior to death. The neuropathologic findings of a progressive tauopathy including the presence of numerous neurofibrillary tangles (NFTs), rare neuritic plaques, and widespread expression of TDP-43 (transactive response [TAR] DNA binding protein 43) also require further study. Discussion: The potential prevalence of CTE, as well as the vulnerable populations involved, makes research into this topic crucial. Currently, a comprehensive neurological exam, neuropsychiatric assessment, and standard radiographic techniques such as conventional MRI are the mainstay of diagnosis. There is a pressing need for the prevention of CTE and the development of non-invasive diagnostic tests in order to develop therapies that may be of clinical use to athletes and blast injury veterans during their lifetimes.