Head trauma and neurodegeneration in veterans

Since the beginning of the last century, it has been known that repetitive brain trauma associated with certain sports or activities may cause a progressive neurodegenerative disease later in life. The first observation was reported in 1928 in 23 boxers by Dr. Martland.¹ More recently, it has become evident that the consequences of repetitive brain injury are limited not only to boxers but also participants in other sports and activities. The pathologic entity associated with repetitive head trauma (HT) is currently referred to as chronic traumatic encephalopathy (CTE).² Age at initial exposure, duration of exposure, genetic predisposition, and additional environmental factors have been invoked as contributing to the development of CTE.² Recent pathologic studies performed on athletes with a history of repetitive head injuries have revealed widespread neuronal loss associated with tau-positive protein deposition in neurons, described as characteristic neuropathologic findings in CTE.² CTE cannot, however, be diagnosed with confidence antemortem, and clinically may have features that resemble Alzheimer disease (AD), frontotemporal dementia, Parkinson disease (PD), PD with dementia, and amyotrophic lateral sclerosis (ALS).²