Clinical Features of Repetitive Traumatic Brain Injury and Chronic Traumatic Encephalopathy

Abstract

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease characterized by a distinct pattern of hyperphosphorylated tau (p-tau). Thought to be caused by repetitive concussive and subconcussive injuries, CTE is considered largely preventable. The majority of neuropathologically confirmed cases have occurred in professional contact sport athletes (eg, boxing, football). A recent post-mortem case series has magnified concerns for the public's health following its identification in six high school level athletes. CTE is diagnosed with certainty only following a post-mortem autopsy. Efforts to define the etiology and clinical progression during life are ongoing. The goal of this article is to characterize the clinical concepts associated with short- and long-term effects of repetitive traumatic brain injury, with a special emphasis on new clinical diagnostic criteria for CTE. Utilizing these new diagnostic criteria, two cases of neuropathologically confirmed CTE, one in a professional football player and one in a professional boxer, are reported. Differences in cerebellar pathology in CTE confirmed cases in boxing and football are discussed.

Spontaneous nervous system concussion in dogs: A description of two cases and a review of terminology in veterinary medicine

“…Those at highest risk are professional athletes who participate in contact sports (mainly boxers) and military personnel who are exposed to repetitive blast events (Petrie et al, 2014). Symptoms may begin years after repetitive brain trauma exposure and include memory loss and other cognitive impairments (Stern et al, 2013;Montenigro et al, 2015a). The diagnosis is made postmortem and is defined by the presence of p-tau protein in the form of neurofibrillary tangles, glial tangles and neuropil threads, with widespread distribution throughout the brain (Montenigro et al, 2015a,b;McKee et al, 2015).…”

A Clinical Approach to the Diagnosis of Traumatic Encephalopathy Syndrome

“…Montenigro et al 1,27 reviewed published cases of pathologic CTE to further describe the clinical spectrum of TES and to propose criteria for use in research design, which were not intended to be used clinically for the evaluation of living patients. The authors used data from 202 cases of male athletes with histories of repetitive head trauma who met review criteria for possible, probable, and neuropathologically confirmed CTE.…”

“…Based on their review, Montenigro et al 1,27 proposed diagnostic criteria for TES using only those clinical signs and symptoms that were present in more than 70%of reported cases of CTE, requiring repetitive head trauma, persistence of symptoms for longer than 1 year, and absence of another neurologic disorder that could otherwise account for the symptoms. In addition, at least 1 core clinical feature (ie, cognitive, behavioral, or mood disturbance) and 2 supportive features (ie, impulsivity, anxiety, apathy, paranoia, suicidality, headache, motor signs, progressive decline, or delayed onset) were required for a TES diagnosis.…”

“…However, this design decision results in necessary limitations (eg, increased false-positive findings) in the clinical setting. Montenigro et al 1, 27 proposed that delay of onset and progression were not required features for diagnosis, which limits the ability of these criteria to distinguish postconcussion syndrome or chronic neurocognitive impairment after moderate or severe TBI from TES. Last, Montenigro et al 1, 27 proposed guidelines for probable, possible, and unlikely CTE (underlying pathologic change) based on meeting criteria for TES, which is difficult to support at this time.…”

“…The criteria proposed by Montenigro et al 1,27 were then adapted for the recently proposed UNITE study. 2 This study proposes analyzing the brains and spinal cords of 300 deceased individuals with a history of repetitive head trauma during the next 4 years.…”