Repetitive Head Impacts and Chronic Traumatic Encephalopathy

Ann C. McKee, Michael L. Alosco, Bertrand R. Huber
2016 Neurosurgery clinics of North America  
There are growing concerns that cumulative repetitive head impact exposure through routine participation in contact and collision sports is associated with increased risk of long-term problems in memory and cognition, including the development of chronic traumatic encephalopathy (CTE). CTE is a distinctive neurodegenerative disease that occurs as a result of repetitive head impacts (RHI) including concussion and subconcussion. Like most neurodegenerative diseases, CTE can only be diagnosed by
more » ... stmortem neuropathologic examination of brain tissue. Recently a panel of exerts concluded that CTE is a unique disorder with a pathognomonic lesion that can be reliably distinguished from other neurodegenerative diseases, such as Alzheimer's disease and frontotemporal lobar degeneration. The pathognomonic lesion of CTE consists of a perivascular accumulation of hyperphosphorylated tau protein in neurons and astrocytes in an irregular pattern, and is typically most prominent at the depths of the cerebral sulci. Clinically CTE is associated with violent behaviors, explosivity, a loss of control, depression, suicide, memory loss and cognitive changes. While the exact incidence and prevalence of CTE remain unknown, there is increasing evidence that CTE affects amateur atheletes as well as professional athletes and military veterans. Given the millions of contact sport athletes and military service members who are exposed to RHI each year, CTE has become a major public health concern. There is a critical need for identification of CTE during life, improved understanding of the epidemiology and pathobiology, and the development of effective prevention and treatment strategies for CTE. KEY POINTS • A panel of expert neuropathologists recently defined chronic traumatic encephalopathy (CTE) as a unique neurodegenerative tauopathy characterized by a pathognomonic lesion. The pathognomonic lesion consists of a perivascular accumulation of abnormally hyperphosphorylated tau in neurons and astrocytes distributed in an irregular fashion with a propensity for sulcal depths of the cerebral cortex. • The development of research criteria for the clinical diagnosis of CTE, known as Traumatic Encephalopathy Syndrome (TES), will facilitate clinical research in CTE. • The number of years of exposure to contact sports, not the number of concussions, is significantly associated with more severe tau pathology in CTE, suggesting that repetitive head trauma, including subconcussive injury, is the primary stimulus for disease. • Recent studies in neurodegenerative disease brain bank cohorts suggest that among amateur athletes, changes of CTE are more common than previously recognized. • The development of in vivo biomarkers for CTE to facilitate the diagnosis of CTE during life as well as therapeutic strategies to help individuals with suspected CTE are critically needed .
doi:10.1016/j.nec.2016.05.009 pmid:27637402 pmcid:PMC5028120 fatcat:xqns2j5ebbdcnd44b2gg2jkncu