Mild Traumatic Brain Injury in Sports: What are the Signs?

by Mark J. Ashley

A 19 year old Golden Gloves contender from Texas recently died due to concussive injuries he received during his bout in a regional finals competition. After taking several blows to the head (he was wearing head gear), he was knocked down. He was given a ?standing 8 count? (the referee counts to eight and if the fighter seems responsive in this period of time, the fight continues). When the fight continued, he was knocked down again, causing a period of unconciousness of 7 minutes. By 10 pm the following evening he was pronounced dead at a local hospital. The cause of death was a ?closed head injury.?

After the fight, a ring-side physician had pronounced that the boxer would be fine. Obviously, he was not ?fine.? But how is it that someone can die from what apears to be a minor occurrence? And, what is a mild brain injury?

Mild traumatic brain injury (MTBI) results in a group of symptoms, which can occur following a change of consciousness caused by a traumatic event. Frequently, the alteration of consciousness is brought on by a direct blow to the head, however, such direct trauma is not always part of an injury. In fact, a violent shaking of the head or torso can result in MTBI.

The term MTBI has replaced the more traditional terminology of ?postconcussive syndrome? on the recommendation of the American Congress of Rehabilitative Medicine (1).

The incidence of MTBI is not well documented. While overall incidence figures are available for traumatic brain injury, figures specific to MTBI are difficult to collect due to large discrepancies in classification of the injury. Some research indicates that only 1 in 5 persons suffering a concussion will seek medical attention and receive a diagnosis of concussion. The literature indicates that about 1 in 5 people sustaining an injury of this type will persist in having one or more symptoms lasting longer than one year.

Diagnosis
In general, MTBI is an appropriate diagnosis when there has been a loss of consciousness of 20 minutes or less, neurologic examination shows no focal findings and MRI, CT and EEG are normal. Some diagnosticians include an assessment of post traumatic amnesia (PTA) while others include scores from the Glasgow Coma Scale of 13-15. Many practicing physicians equate concussion only with an extended loss of consciousness and a significant period of PTA. The fact that some diagnosticians include these latter two or three criteria creates a difficulty in obtaining a uniform application of the diagnosis.

The incidence of MTBI in professional sports is not well understood, though some incidents are witnessed by audiences worldwide. When celebrities such as Steve Young of the San Francisco 49'ers or Dan Marino of the Dolphins is injured in this way there is great notice taken. When these individuals return to play the next week, the assumption is made by the general public that MTBI or concussion produces no long lasting effects.

In actual fact, however, many researchers hypothesize that brain injury is cumulative (2). Each occurance of injury results in the loss of a certain number of brain cells. As a person accumulates injuries, they experience increasing losses of neurons, until a threshold is reached. Surpassing this threshold, the individual begins to experience more overt symptoms associated with MTBI.

Such symptoms include impairment in attention, concentration, memory, reasoning, balance and coordination. In some, the cognitive deficits can be profoundly disabling. In others, somatic complaints are equally prevalent. Complaints of pain, in particular in the neck and back, are not uncommon. Headache pain is also frequently reported.

Mechanisms of Injury
As the brain experiences the forces applied to the cranium the laminar structure of the brain itself may become unstable. The brain is composed of six different layers of varying thickness and densities in varying regions of the brain. Structures that course between these layers enroute to other areas of the brain are susceptible to damage when these layers of the brain shift. Such damage is sometimes referred to as shearing or diffuse axonal injury. Axons, dendrites and blood supply are all susceptible to damage of this type.

It is thought that following MTBI, the brain's laminar structure becomes unstable for a period of time, that period of time being related to the severity of the injury. The risk of severe injury or death arising from a second trauma is thereby increased following MTBI. Too many players have returned prematurely to the field, only to sustain a seemingly mild blow and suffer severe, permanent, pervasive, brain injury or, in some cases, death.

CNS has had an opportunity to consult with professional sports teams concerning the danger of undiagnosed MTBI. We have found that there is a considerable lack of understanding of these issues by trainers, equipment coaches and players alike. Many players become superstitious about their equipment, fearing that any change will alter the outcome of a pending game. Equipment coaches can often guide players into equipment that would be substantially safer, however, the weight or configuration of the equipment may not be accepted by the players.

An interesting conflict is present in the players? desires to perform and the teams? long term financial interests in the player. There does not appear, though, to be much control exercised in restraining players from returning to play prematurely, or in requiring the use of safer equipment.

Guidelines
A very important step has been taken by The Sports Medicine Committee of the Colorado Medical Society. This group developed guidelines for the management of concussion in sports in 1990. Their work has been endorsed by the American Academy of Pediatrics, American Academy of Sports Physicians, American College of Surgeons Committee on Trauma, Colorado Society of Neurologists, University of Colorado, Department of Neurology and Division of Neurosurgery. The guidelines allow for a grading of injuries with specific return to play guidelines for each level.

Grade One injuries result in confusion without amnesia and no loss of consciousness. This is the common type of sport related concussion. The player should be removed from the event and evaluated before re-entering the contest. The sideline evaluation includes being asymptomatic (no headaches, dizziness, impaired orientation, impaired concentration, memory dysfunction) both at rest and following exertion for at least 20 minutes. A second Grade One injury eliminates the player from the contest entirely. Imaging by CT or MRI is recommended for symptoms that persist longer than one week or in the event that symptoms worsen. A player who sustains three Grade One injuries should be terminated for the season. No further contact sports should be engaged in for three months and only then if the person is asymptomatic at rest and after exertion.

Grade Two injuries result in confusion with amnesia but no loss of consciousness. In these cases, the person should be removed for the balance of the game. A complete neurological examination should follow with the individual being monitored closely for 24 hours to watch for signs of developing brain injury. In these cases, return to play after a first concussion can be as soon as one week after the athlete is asymptomatic at rest and after exertion. After a second Grade Two injury, return to play should be deferred for at least one month. Termination for the season should be considered. Three Grade Two injuries mandate termination of the player's season. Imaging should be performed for any symptoms that persist for a week or worsen. A neurologic examination should be repeated prior to return to play.

Grade Three injuries result in loss of consciousness for any period of time. The athlete should be transferred to the nearest hospital by ambulance with cervical spine immobilization. Neurologic examination should be performed with imaging as indicated. Return to play following Grade Three injury should be after one month furing which the player is asymptomatic at rest and after exertion for at least two weeks. If the player is asymptomatic, conditioning drill can be resumed after one month with no actual contact. A season is terminated following two Grade Three injuries or by an abnormality on imaging. Return to any contact sports should be seriously discouraged.

These guidelines take the decision making responsibilities of whether to return a player to the field out of the hands of coaches, trainers, players, and parents, and create clear definitions and a course of action to be specifically followed. They also allow for a common understanding and medical approach among physicians.

Further information about these guidelines is available by contacting the Brain Injury Association of Colorado at: 303-355-9969 or the Colorado Medical Society at: 303-779-5455.

References:
1. ACRM. (1993). Journal of Head Trauma Rehabilitation, 8(3), 86-87.
2. Gronwall, D. & Wrightson, P. (1975). Cumulative effect of concussion. The Lancet. Nov. 22, 995-997.

The author, Mark J. Ashley, is a co-founder of the Centre for Neuro Skills and President of CNS in Bakersfield, California.

Current News:
Computers Facilitate Concussion Diagnosis