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Concussive brain injuries can have lifelong impact


Wade Evanson’s “From the Sidelines” column, “Injuries a Part of the Game ...” (News-Times, Nov. 2, 2016) is correct in several regards. Football does indeed teach important life lessons: teamwork, working toward long term goals, winning (and losing) with class and enduring hardship to improve and excel.

All active sports, not just football, involve injuries — bruises, sprains, lacerations, dislocations and broken bones — which usually heal with no long term concerns. But brain injuries, also called concussions, even if classified as “minor” traumatic brain injuries (MTBI) are different. Brain injuries after recovery can be subtle or dramatic but last a lifetime.

Recent work by Dr. Ann McKee (Boston Medical College) and others reveal two new important facts. Even minor concussions have cumulative effects. It is not just the “big hit,” the “dingers” and “bell ringers” that renders a player confused or unconscious that are dangerous. And it is now documented that the hundreds and thousands of typical “normal” head impact events from blocking and tackling have cumulative and significant lifelong health impacts.

McKee’s post-mortem brain biopsies of over 100 professional football players show universal and massive brain damage, now known as CTE or Chronic Traumatic Encephalopathy. Symptoms of CTE are depression, drug abuse, violence, irrational behavior and suicide.

When deaths occur in high school football, brain or spinal injuries are usually causal. Particularly dangerous is secondary impact syndrome when a player sustains an MTBI, continues to play and receives a second brain impact.

Basketball, lacrosse and soccer also involve both acute and cumulative brain injuries. CDC data notes significant incidence of concussion when basketball players’ heads strike hardwood floors. Helmets and other head gear reduce TBI by reducing the amount of peak or shock energy which reaches the brain mass. The skull and fluids surrounding the brain also reduces the amount of energy reaching the brain mass.

Brain injury events or impacts are described in “g’s” or “gravities” of acceleration or deceleration which the brain mass experiences. The duration of a brain impact event is also critical. Bullet ricochets can produce high g’s but are so quick (fractions of a millisecond) that the brain mass does not accelerate. In football “threshold” levels for linear impact brain injury appears to be 70 to 90 g’s for durations of 12 to 20 milliseconds.

Rotational (versus linear) acceleration impacts occur when football helmets, (particularly face guards) are struck laterally, causing rapid rotational acceleration. The “bobble head” design of humans is an evolutionary design to convert linear impact blows to rotational acceleration. When the skull and brain rotate away from an impact, the duration of the event is extended. Peak energy levels are lowered and injury reduced. “Threshold” for brain damage from rotational acceleration appears to be in 4,000 to 7,000 radians per second per second range. (Snell Labs and King et al, Med. College of Wisconsin, Dept. of Neurosurgery, 2003).

The greatest mitigation factor for players to not be injured in a single acute event appears to be visual awareness of the impending blow. The autonomous nervous system appears to be able to tense neck and shoulder muscles fast enough to resist effects of the impact if the impending strike is seen. Because children and infants often do not expect to be slapped and because head slaps generate both rotational and linear accelerations, children can be easily brain injured by slapping.

Participation in young-player football leagues is declining significantly. Parents have good reason to be cautious. Too often overzealous coaches and mismatched players regarding skills, size and conditioning can lead to both body and brain injuries.

New protocols, awareness training for coaches and players, on field penalties, and Return To Play (RTP) protocols have emerged. Many states have imposed Concussion Protocols. Oregon has OCAMP, Oregon Concussion Awareness and Management Program.

New technologies are emerging. Better helmets are good and are being adopted. Shock sensors connected to helmets or in the chin strap cup don’t indicate what is experienced by the head mass and brain. Reebok’s skull cap “Checklight” and new mouth guards with accelerometers — which report actual head mass impact event g levels — show great promise but are slow to market for several reasons. De facto medical device liabilities, patent conflicts and high incidence of “false positives” are ongoing issues.

A basic problem persists; a 70g (or even a 100g) linear brain mass impact event can be serious or innocuous due to known and unknown variables. Baseline testing and sideline neuro-cognitive and balance testing are

helpful but are not widely used. The simple and immediate and inexpensive “drop stick reaction time test” could be routinely used by every trainer and coach at every game. But is not.

New “heads up” tackling and “defenseless player” and “targeting” penalties are important steps making football safer at all levels. Inadequate testing and certification procedures by NOCSAE (National Operating Committee on Standards for Athletic Equipment) are being addressed. ASTM’s F08 Committee continues to study, develop and define safety standards and performance criteria for athletic equipment including concussion mitigation innovations for helmets and mouth guards and other emerging technologies.

How concussion risks in sports can be reduced is emerging. Why new and existing concussion mitigation tools are not more widely adopted is the question.

Don B. Hennig of Forest Grove is a principal of Bio-Applications LLC, a Portland sports technology development firm.