New insights into specific types of brain abnormalities

Jul 13 2011

Postmortem analysis of the brains of ten professional athletes with chronic traumatic encephalopathy (CTE) provides new insights into the specific types of brain abnormalities associated with this diagnosis, reports a study in the July issue of Neurosurgery, official journal of the Congress of Neurological Surgeons. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health.

The findings may help to refine the cellular criteria for making the postmortem diagnosis of CTE, provide initial clues as to some possible subytpes, and improve identification of cases. The study was led by Drs. Bennet I. Omalu and Julian Bailes of the Brain Injury Research Institute at West Virginia University.

Detailed Information on Brain Abnormalities in CTE

The researchers performed a detailed evaluation of autopsy brain specimens from 14 professional athletes and three high school football players who died unexpectedly. The goal was to take an in-depth looks at the cellular-level abnormalities associated with chronic traumatic encephalopathy (CTE)—a progressive neurodegenerative disease caused by repeated head trauma, seen especially in high-level competitive athletes.

Patients with CTE develop mood disorders, cognitive dysfunction, and other psychiatric symptoms, typically occurring years after a history of repeated concussions. Drs. Omalu and Bailes have played a pivotal role in CTE research, having reported on the first three cases of CTE in American football players.

Of the 14 professional athletes in the study, ten had autopsy brain findings consistent with a diagnosis of CTE. The CTE cases were seven football players, two wrestlers, and one boxer. Most died from non-natural causes—mainly suicide or trauma.

The authors present a detailed analysis of the neuropathological findings in their cases of CTE. The main feature was "neurofibrillary tangles" (NFTs) and "neuritic threads" (NTs) scattered in different areas of the brain. The brains also show evidence of localized areas of brain trauma occurring many years previously.

Findings Suggest Possible 'Emerging' Subtypes

None of the athletes with CTE had the characteristic brain atrophy (shrinkage) of Alzheimer's disease. None of the brains showed the widespread amyloid deposits typical of Alzheimer's disease, but some had scattered to frequent amyloid deposits. Although there are not yet enough cases to develop a true classification system, the authors identify some possible "emerging phenotypes" of CTE, based on the number and location of NFTs and NTs and amyloid deposits.

The researchers also examined the brains of three high school football players who died of trauma sustained during competition. None of these young athletes met criteria for a diagnosis of CTE. However, one brain showed early, "incipient" abnormalities similar to those of CTE brains, likely related to repeated brain injury.

Since the first reported case in 2002, there has been growing concern about CTE and other consequences of repeated head trauma and concussions in football players and other athletes. The findings have led to renewed discussion of the consequences of head trauma—not only in athletes, but also in other high-risk groups such as combat veterans. The Brain Injury Research Institute was created to study the short and long-term impact of brain injury and concussions and the development of CTE.

Drs. Omalu and Bailes and colleagues hope their findings will contribute to further research into the neurological and psychosocial impact of CTE. In addition to proposing some possible subtypes of CTE, they suggest a set of pathological tests to be performed in diagnostic investigation of possible CTE. They believe that "CTE diagnosis and surveillance should become intrinsic components of routine patient care work-ups and routine hospital/medical examiner autopsies in high risk cohorts like athletes."