Diagnosing Sport Concussions
Concussion has proven difficult to diagnose and treat. Most sports-related concussions occur without the loss of consciousness or other obvious signs of brain trauma. Technological tools don't always help, either, since most concussions can't be identified or diagnosed using brain scans.
Sports medicine clinicians have also found that diagnosis can be problematic when athletes are unwilling to admit or recognize their symptoms from being concussive in nature. Many just want to get back to the game.
In addition, there are some individuals who experience a delay before concussion symptoms are present. Such athletes might get an "all clear," go back to the game, and later lose consciousness or start having convulsions.
Compounding the difficulty in diagnosing concussion is that on a sporting field, medical personnel are often pressured to make a quick assessment of an athlete in order to return to play. Without a simple way to check for concussion, it is likely that in this high-pressure situation, many athletes are sent back to play even though they are indeed injured.
In a new research review, a team of scientists examined the evidence for determining the lowest threshold for diagnosing a sports-related concussion.
The team of researchers reviewed the ways concussion is defined. While a definition was established in 1966, a new, more thorough, definition for the term "concussion" was developed in 2002 by professionals of sports medicine. Concussion is, "a complex pathophysiological process affecting the brain, induced by traumatic biomechanical forces". The definition also outlines the possible causes: direct blows to the head, face, neck, or other body part with the force transmitted to the head. It usually results in a rapid onset of short-lived neurological impairment.
The team of researchers involved in this study also went about distinguishing the difference between concussion and mild traumatic brain injury (mTBI), which are often used synonymously. A concussion is a type of mTBI, but not all mTBI is a concussion. Therefore, the researchers argued, the terms should not be used interchangeably.
Understanding what happens in the brain during in a concussion has also been difficult. Most experiments in this area have been on animal models, which is limiting. The authors of the study noted that changes such as an altered brain activity level, an altered glucose metabolism, and alterations in cerebral blood flow are all possible with a concussion.
The review included a discussion of concussion-induced changes in brain metabolism, during which the brain tissue is more vulnerable immediately following a concussion. If a second concussion happens during this vulnerable period, the effects may be more significant and can cause more dramatic brain damage.
While it has been discovered previously that a tolerance to head impacts varies among people, and this may be genetic, there is no way to identify the most vulnerable among us.
The researchers recommended that all head injuries should be treated as a concussion until proven otherwise, and they pointed out that such a determination is not possible until hours after injury. Athletes should be removed from play and observed for physical signs, behavioral changes, self-reported concussive symptoms, amnesia, confusion, or balance problems. This means it is not enough to do an initial medical assessment; there should be an ongoing observation of the injured athlete for several hours.
McCrory P, et al. What is the lowest threshold to make a diagnosis of concussion? British Journal of Sports Medicine 2013: 47:268-271.