Participation in Contact or Collision Sports in Athletes With Epilepsy, Genetic Risk Factors, Structural Brain Lesions, or History of Craniotomy

Vincent J. Miele, M.D.; Julian E. Bailes, M.D.; Neil A. Martin, M.D.

Disclosures

Neurosurg Focus. 2006;21(4) 

In This Article

Epilepsy

Epilepsy affects approximately 2% of the population,[37] and the attitudes toward participation of this population in contact sports have changed over the years, from avoidance to encouragement. Several issues are unique to individuals with epilepsy. It is conceivable that exercise could exacerbate seizures either directly, through hyperventilation, or indirectly, by alteration of the levels of anticonvulsant drugs. Trauma from contact or collision sports resulting in recurrent minor head injuries could worsen epilepsy. These risks are theoretical for the most part, and very few case reports support these notions. It has become increasingly clear that a more reasoned approach is to individualize the decision for each sport and each patient based on a risk–benefit analysis, which leads to few restrictions overall.

Although it is possible that the occurrence of a seizure during certain athletic events could cause a substantial in crease in risk to the participant, this pertains more to sports involving heights, such as gymnastics or horseback riding.[37] Some types of seizures could leave a patient vulnerable from lack of attention to impending injury, as in being blind-sided during football.[30] Therefore, when considering if an athlete with epilepsy should participate in contact or collision sports, one consideration is the type of seizure disorder the athlete suffers from. Generalized tonic –clonic (grand mal) seizures may result in unprotected falling. This is especially true with atonic seizures that result in a sudden loss of muscle tone. Seizures characterized by unprotected falling put patients continually at risk of injury from striking the playing surface or another object. Athletes suffering absence seizures consisting of brief (typically 3–10 seconds), motionless, nondistractible staring usually maintain their balance. This condition places the participant at an increased potential risk of injury from being unable to protect him- or herself during contact sports. Simple partial seizures often do not affect consciousness. Therefore, this type of seizure is unlikely to result in injury as a result of unanticipated falls or unprotected blows during participation. Complex partial seizures often do result in an alteration but not a loss of consciousness, and usually are 1 to 2 minutes in duration, followed by a brief period of confusion. Unlike players who suffer generalized seizures, athletes with complex partial seizures are often amnestic to the event, and it may go unnoticed until abnormal behavior is observed, such as wandering around the playing field. Although complex partial seizures are similar to absence seizures in that they may involve only staring, the duration is much longer, which theoretically increases the athletes' exposure to injury from an inability to protect themselves.[30] Obviously, seizures that begin as partial ones may generalize, with the same specific risks as for primary generalized seizures noted earlier.

One of the strongest arguments for disallowing participation in contact or collision sports is that the multiple minor head traumas associated with such participation could exacerbate the condition. There is only one report of seizures caused by blows to the head[19] and no evidence that contact sports are harmful for most patients with epilepsy.[4] It is also theoretically possible that repeated or severe head injury sustained during contact sports could exacerbate seizures in a patient known to have epilepsy, an argument that initially led to complete prohibition of participation in sports for this group.[30] Although evidence does exist that head injury can cause epilepsy, this association only holds true for severe traumas.[2,3,45–47] There is no consistent report of increased risk of subsequent epilepsy from a typical mild head injury in the general population. Typical sports-related head injuries are so mild that they are extremely unlikely to be associated with epilepsy.

Numerous factors have been discussed that could cause this increase in seizure frequency and/or severity, including repeated head trauma, aerobic exercise, hyperventilation, physical and psychological stress, and changes in antiepileptic drug metabolism.[30] Fear that increasing aerobic exercise may exacerbate seizures was magnified by several case reports of patients whose seizures were "triggered" by exercise.[53,55,57,68] Because hyperventilation has been shown to trigger absence seizures when performed at rest during a routine electroencephalography study, it was extrapolated that seizures could also be triggered during exercise-induced hyperventilation. Differences in the physiology of resting compared with exercise-induced hyperventilation make this unlikely. Increased metabolic demand during exercise is the cause of increased respiratory effort, a compensatory response to avoid hypercapnia. This is in contrast to the hypocapnia induced by resting hyperventilation that results in cerebral vasoconstriction. This promotes alkalosis and can make absence-related abnormalities found on electroencephalography studies more pronounced. Because the increased respiratory effort during exercise is a response to acidosis, it has the opposite effect of causing the relative suppression of abnormalities seen on electroencephalography. In fact, exercise-induced hyperventilation may even produce a refractory period that can delay the activating effects of resting hyperventilation.[29,34] The current thinking is that, although exercise does initiate exacerbation of seizures in rare cases, on average it reduces seizure frequency during prospective formal evaluation.[28,54] In fact, interictal epileptiform activities remained unchanged or decreased during or immediately after exercise in the majority of patients studied, even in some patients with exercise-associated seizures.[29,34,55] Additionally, because of the general health and psychological benefits of aerobic exercise, it is recommended for most patients, although it must be recognized that this type of exercise will trigger seizures in some.

An additional consideration in this population is the effect of exercise on drug metabolism. It is well known that exercise induces hepatic microsomal enzymes. This can result in an increase in medication clearance, requiring a dose adjustment to maintain efficacy.[26,31] In addition, the release of fatty acids may compete for protein binding sites and displace anticonvulsant medications, leading to a higher free fraction of highly protein-bound drugs.[30]

Current opinion is that participation in contact or collision sports benefits individuals with epilepsy in many ways, including improvements in seizure control, mood, and quality of life. Contact sports such as football, hockey, and soccer have not been shown to induce seizures, and athletes with epilepsy should not be prohibited from participation.[37] There is little evidence to justify summarily excluding patients with epilepsy from most sports, but some common sense rules apply.[13,30,33,80] Obviously, care must be taken in sports involving heights, such as gymnastics,[37] and athletes with epilepsy must be evaluated on an individual basis; however, no significant evidence exists to suggest that contact sports are harmful to these individuals.

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