Participation in athletic activities is increasing at all age levels. All participants may be potentially exposed to physical harm as a result of such participation. Physical harm is more likely to occur in athletic events where collisions between participants frequently occur (e.g., football, field hockey, lacrosse, ice hockey, soccer and the like). In connection with sports such as football, hockey and lacrosse where deliberate collisions between participants occur, the potential for physical harm and/or injury is greatly enhanced. Approximately 300,000 athletes incur concussions in the United States each year. This may be a conservative estimate because many minor head injuries go unreported. Although most concussions occur in high-impact sports, athletes in low-impact sports are not immune to mild traumatic brain injury. Head injuries are caused by positive and negative acceleration forces experienced by the brain and may result from linear or rotational accelerations (or both). Both linear and rotational accelerations are likely to be encountered by the head at impact, damaging neural and vascular elements of the brain.
At the school level, school authorities have become sensitive to the risk of injury to which student participants are exposed, as well as to the liability of the school system when injury results. Greater emphasis is being placed on proper training and instruction to limit potential injuries. Some players engage in reckless behavior on the athletic field or do not appreciate the dangers to which they and others are subject by certain types of impacts experienced in these athletic endeavors. Unfortunately, the use of mouth guards and helmets does not prevent all injuries. One particularly troublesome problem is when a student athlete experiences a head injury, such as a concussion, of undetermined severity even when wearing protective headgear. Physicians, trainers, and coaches utilize standard neurological examinations and cognitive questioning to determine the relative severity of the impact and its effect on the athlete. Return to play decisions can be strongly influenced by parents and coaches who want a star player back on the field.
The same problem arises in professional sports where the stakes are much higher for a team, where such a team loses a valuable player due to the possibility of a severe head injury. Recent medical data suggests that lateral and rotational forces applied to the head and neck area (for example, flexion/extension, lateral flexion, and axial rotation) are more responsible for axonal nerve damage than previously thought. Previous medical research had indicated that axially directed forces (such as spinal compression forces) were primarily responsible for such injuries.
Identifying the magnitude of acceleration that causes brain injury may assist in prevention, diagnosis, and return-to-play decisions. Most field measurements assess the acceleration experienced by the player with accelerometers attached to the helmet. The following show some attempts for measuring the impacts to the skull and brain while the player is participating in a sporting activity. U.S. Pat. No. 5,539,935, entitled “Sports Helmet,” issued on Jul. 30, 1996 and U.S. Pat. No. 5,621,922, entitled “Sports Helmet Capable of Sensing Linear and Rotational Forces,” issued on Apr. 22, 1997 are examples of some of those attempts. Both patents relate to impact sensors for linear and rotational forces in a football helmet. These devices test the impact to the skull of a player. If an athlete suffers a concussion, for example, it will be possible to determine if the relative magnitude of an impact is dangerously high relative to a threshold to which each sensing device is adjusted, taking into consideration the size and weight of the player.
Another attempt performs testing impact acceleration to the head with an intraoral device which provides acceleration information of the brain in various sports. Other attempts have been made, however all these attempts can be costly to implement and fail to provide full historical medical information to coaches, trainers and medical professionals in real-time for dozens of players at a time on one or more adjacent fields.