What Is a Sports Concussion?Concussions are traumatic head injuries that occur from both mild and severe blows to the head. Some head injuries may appear to be mild but research is finding that concussions can have serious, long-term effects, especially repeat head injuries or cumulative concussions.
A concussion is typically caused by a severe head trauma during which the brain moves violently within the skull. The brain cells all fire at once, much like a seizure. Some studies show that patients who suffer a concussion appear to have the brain activity of people in a coma.
A concussion may result from a fall in which the head strikes against an object or a moving object strikes the head. A suddenly induced turning movement such as a blow that twists the head (like a punch to the side of the face) is more likely to produce unconsciousness. However, significant jarring in any direction can produce unconsciousness.
In 2004, data has collected from the head impact telemetry system used in the NFL concussion studies found that 58 of 623 (9.3 percent) of professional football players who suffered a concussion also had a loss of consciousness.
- Early Concussion Symptoms May Include:
- Memory loss
- Unequal size pupils
- Vision changes
- Late Concussion Symptoms May Include:
- Memory disturbances
- Poor concentration
- Sleep disturbances
- Personality changes
Sports Concussions Linked to Depression and Cognitive DeficitsDepression is one of the many symptoms experienced by athletes following concussion. In fact, some research finds the prevalence of depression in head trauma patients can be as high as 40 percent. Several studies have also shown a link between a history of brain injury and a higher probability of developing major depression later in life.
- One study on concussion in athletes from the Montreal Neurological Institute of McGill University identified a neurological basis of depression in athletes who have had concussions. Imaging tests done with functional MRI on athletes who had depression following a concussion showed the same pattern of brain activation as patients with major depression.
- Another study found that of 2,552 retired pro-football players, over 11 percent of those with a history of multiple concussions also had a diagnosis of clinical depression. Players reporting three or more previous concussions were three times more likely to be diagnosed with depression than those with no history of concussion.
A study by researchers at the University of Illinois at Chicago College of Medicine reported finding structural changes in the white matter of the brains of patients with head injuries, with the most severe head injuries showing the most structural change. These structural changes correlate to cognitive deficits in thinking, memory and attention.
They also found that some mild head injuries caused damage only to the outer surface of the nerve (the myelin sheath of an axon), which may be able to be repaired, but more severe head injuries caused damage to the axon itself, which may not be as easily repaired. If an axon is severed, it is unlikely that it can repair itself.
Concussion in Skiers and SnowboardersCanadian researchers found that the occurrence of both spinal cord and traumatic brain injury appears to be increasing worldwide. They reported that these increased injury rates coincide with an increase and acceptance of higher speeds on the slopes and more acrobatic maneuvers, such as jumping and twists.
They also reported that wearing a helmet can reduce the risk of head injury by up to 60 percent and highly recommend helmets for skiers and boarders.
Also see: Common Skiing and Snowboarding Injuries
According to researcher Mark Lowell, allowing an athlete to return to play too early after any head injury increases their chance of more serious brain injury. Because signs of a mild concussion -- confusion, disorientation and memory loss -- may disappear within minutes and may not be reported by the athlete, athletes are too often allowed to continue playing or return to a game before their brain has had adequate time to heal.
Concussion Assessment and Testing in AthletesDeciding when an athlete should return to sports after a concussion remains a matter of controversy within the medical community. However, various research projects continue to learn more about concussion assessment and evaluation.
In 2010 researchers at the University of Michigan's Department of Physical Medicine and Rehabilitation developed a simple and inexpensive reaction time test that may help identify athletes who have a head injury that is serious enough to require time off from sports.
Researchers at the University of Pittsburgh's Sports Medicine Center developed a computer program, Immediate Post-Concussion Assessment and Cognitive Testing system, or ImPACT, which measures an athlete's memory, reaction time and processing speed in order to help determine when an athlete can safely return to sports after a head injury.
The test measures an athlete's baseline results at the start of a season. They retest any athlete who sustains a head injury or concussion. The results of the testing provide an objective assessment of whether the athlete is healthy enough to return to play. The ImPACT program is currently used at many high schools and colleges, as well as the National Football League and National Hockey League.
More About: Head Injury and Sports Concussion
Pellman, Concussion in the National Football League: an overview for neurologists, Neurosurgery 2004.
Jen-Kai Chenet al. Neural Substrates of Symptoms of Depression Following Concussion in Male Athletes With Persisting Postconcussion Symptoms,Archives of General Psychiatry. 2008;65(1):81-89.
Kraus MF, et al. White matter integrity and cognition in chronic traumatic brain injury: a diffusion tensor imaging study. Brain. 2007 Oct;130(Pt 10):2508-19. Epub 2007 Sep 14.
Ackery, et al. An international review of head and spinal cord injuries in alpine skiing and snowboarding. Injury Prevention 2007; 13: 368-375.
Recurrent Concussion and Risk of Depression in Retired Professional Football Players. Medicine & Science in Sports & Exercise. 39(6):903-909, June 2007.