Until very recently, impact sensors - accelerometers measuring the forces which, when transmitted to the brain, cause sports-related concussions - were only used by scientists in conducting research.
The last several years, however, have seen a growing number of companies introduce to the consumer market the first generation of impact sensors intended for real time monitoring of impacts to the heads of athletes in actual games and practices.
As is often the case with new technology-based products, the sensors in initial use at some colleges, and by a small but growing number of high schools around the country - including the football program at Newcastle High School in Oklahoma featured in the new PBS  documentary, "The Smartest Team: Making High School Football Safer,"  - are still relatively expensive, and they are just now being tested extensively under real world conditions.
As a result, only time will tell whether they will fulfill the promise that many in the concussion community see them as having, although I, for one, think they will eventually revolutionize the way in which athletes are identified for remove-from-play screening on the sports sideline.
Since I began writing about the use of impact sensors as a technological "end around"  the problem of chronic underreporting  of concussions - and especially since "The Smartest Team" began being broadcast widely on PBS stations around the country - I have been getting a lot of questions about impact sensors.
Fortunately, as result of my first-hand experience, working closely the past two football seasons with sensor manufacturers and the Newcastle football program, and from covering the concussion beat, along with a team of experts and staff journalists, for the past thirteen years, I believe MomsTEAM and I are in a unique position to explain just what impact sensors are all about.
To help parents, coaches, athletic directors, booster clubs, and sports program administrators understand what this cutting-edge technology does - and, just as importantly, what it doesn't do, here are answers to the questions MomsTEAM is most frequently asked about impact sensors:
Answer: Impact sensors are small, highly sophisticated electronic devices designed to measure and, in many cases, record in real time the number and force of impacts athletes sustain during games or practices. Most sensor systems send impact data wirelessly via Blue Tooth connection to a dedicated monitor, iPhone, iPad or laptop on the sports sideline. In some products, the sensor triggers an audible or visual alarm to alert sideline personnel to a high impact hit.
Answer: While impact sensors take a number of different forms (ie. installed inside or on the outside of a player's helmet, embedded in a mouth guard, helmet chin strap, skull cap, head band, or ear bud, for instance), all are essentially designed to do the same thing: alert coaches, athletic trainers, team doctors, other sideline personnel and/or parents about high-risk single and multiple head impacts in order to improve the rate at which concussions are identified. Some also record data on impacts to a player that day, that week, that season, and over the course of their career.
Answer: Early identification is critical because if sideline personnel suspect that an athlete has sustained a concussion or an even more serious brain injury, they can immediately remove them the game, eliminating the risk of further injury. If a concussed athlete is quickly removed from a game or practice, most will recover without incident fairly quickly.
If, however, a concussion or even more serious brain injury goes undetected and an athlete is allowed to continue playing, studies suggest that recovery from concussion, when the concussion is ultimately detected and diagnosed, is likely to take longer. In addition, delayed identification increases the risk of long-term problems such as early dementia, depression, more rapid aging of the brain, or of the devastating degenerative neurological condition known as chronic traumatic encephalopathy or CTE  (although medical science has not come close to quantifying that risk). In extremely rare instances, a player who continues to play with concussion symptoms can suffer catastrophic injury or death from second impact syndrome , a form of diffuse cerebral swelling. It is thus critically important that athletes with concussion be identified and removed from play as quickly as possible.
Answer: Unfortunately, no. Studies published over the past ten years have consistently found that concussions are significantly under-reported by athletes, with at least half, and perhaps many more, going unreported. One 2013 study, for instance, found that high school athletes only reported 1 in 7 impacts they classified as "dings" or "bell-ringers," many of which are likely concussions.
Answer: For a number of reasons.
Some athletes don't report because they don't know what the symptoms are, or because the concussions they have suffered adversely affect their judgment and cognition, so, even if they do know the symptoms, they don't recognize that they are experiencing them.
Unfortunately, most don't report because a deeply engrained culture in contact of contact and collision sports tells them not to; they don't report because they don't want to disappoint teammates, coaches, and parents by removing themselves from the game; or they fear losing playing time or their starting position.
The laws  of all but a few states now mandate that athletes with suspected concussion not only be removed from the game or practice in which they are participating, but not permitted to return that same day, and obtain written authorization to return to play from a health care professional with expertise in the identification, diagnosis, and management of concussion. The laws, some experts fear, make athletes even less willing to report experiencing concussion symptoms because they know that, if they do, they will be benched.
Answer: Yes, it is true that 47 of 50 states have passed laws requiring that athletes and their parents sign forms acknowledging receipt of information about concussion signs and symptoms and the dangers of continuing to play with concussion. Unfortunately, however, recent studies suggest that, education of athletes about the symptoms of concussion and the dangers of continuing to play with such symptoms, has not resulted in increased reporting, with athletes continuing to resist honestly self-reporting experiencing symptoms or voluntarily removing themselves from game action. (what a new report  from the Institute for Medicine and the National Research Council terms a "culture of resistance.")
The same studies suggest that athletes may be more likely to self-report if they feel safe  in self-reporting, in other words, when they don't fear adverse repercussions if they report in terms of decreased playing time, losing their starting positions, or being embarrassed by the coach in front of their teammates for their lack of toughness, such as, for example, by being labeled a "wimp" (or worse).
This has led an increasing number of experts to recommend that concussion education should be as much about removing the stigma associated with reporting and changing the attitudes of players, coaches, and parents towards reporting as it is about educating them about concussion signs and symptoms.
The problem is that no such programs yet exist, and even if they did, and were implemented on a widespread basis, it is unclear whether such a shift in emphasis in concussion education would achieve any meaningful increase in rates of self-reporting. The reason, again, is that it would not only require a paradigm shift in the "warrior" culture  of contact and collision sports, but a fundamental change in a risk-taking attitude, which is a part of the very nature of adolescence.
Answer: Relying on the observational skills of sideline personnel is problematic for a number of reasons. To begin with, the signs of concussion are often either subtle or non-existent, so they escape detection by sideline personnel. (Gone are the days when it took a player's loss of consciousness or heading to the wrong sideline or end zone to raise a red flag about possible concussion.) Many escape detection by even well-trained sideline personnel. (One Canadian study, for instance, found that physician observers in the stands identified concussed athletes at a rate seven times that of coaches and athletic trainers on the bench).
Add in the possibility that sideline personnel responsible for monitoring athletes for signs of concussion, such as team doctors and athletic trainers, may be away from the sideline attending to other injured athletes when a player sustains a high force blow, or, even if they are watching the field/court/rink, may miss significant impacts because they occur away from the play, and one can see why better concussion detection methods are needed.
Answer: Exactly. Impact sensors don't depend solely on athletes to remove themselves from games or practices by reporting concussion symptoms, or on game officials or sideline personnel to observe signs of concussion. By monitoring head impact exposure in real time, sensors give sideline personnel an additional tool to identify high-risk impacts so they can consider performing a concussion assessment, or, alerted to the fact that an athlete has sustained a heavy hit, can watch them more closely for concussion signs. In a very real sense, sensors are another set of "eyes" watching for concussed athletes.
Answer: No. It needs to be absolutely clear that impact sensors do not diagnose concussion, and should not be used for that purpose. This is because concussion researchers have not yet found the impact threshold above which concussion is highly likely. (Indeed, because the impact forces that result in concussion vary from athlete to athlete, are likely affected by numerous variables, and indeed may change from moment to moment, game to game, and over time, it may be that such an impact threshold - appropriately labeled by some researchers as the concussion "holy grail" - will never be found. )
Because impact sensors are not diagnostic, a team equipping its players with sensors must be careful not to rely on the data transmitted by the sensors, or the triggering of an alert or alarm, as in any way determinative of whether an athlete has or has not suffered a concussion. Nor are they designed to make any type of recommendation about the ability of a player to play or not play.
As Danny Crossman, CEO of Impakt Protective, the Canadian company that manufactures the Shockbox sensors featured in the "The Smartest Team," notes, "The main point of the helmet sensors [i]sn't to say, 'You got a concussion.' The point [i]s to say, 'That head took a hit. ...[The athletic trainer] can then use his training, intuition, and his eyes, number one tool is his eyes, to say ‘what just happened there?'"
Answer: First, of all impact sensors are not intended to replace sideline observers, game officials, coaches, and teammates. They still need to be present and ever-vigilant about watching for signs of concussion  or heavy hits that could cause concussion. If they have any reason to suspect a concussion (whether because they see an athlete exhibiting concussion signs or because he or she took a high impact hit), then they need to conduct a sideline screening for concussion using one or more of a battery of assessment tools already shown by studies to be reliable in making the initial remove-from-play decision (eg. Standardized Assessment of Concussion or "SAC" , Sport Concussion Assessment Tool Version 3 or "SCAT3" Balance Error Scoring System or "BESS" , King-Devick Test " Maddocks" questions ) or one of a number of new assessment screens being developed and tested.
The critical point to always keep in mind about Impact sensors is that they are just another tool in the concussion toolbox or, put another way, another set of eyes, with which to identify athletes who (a) may have sustained impacts of sufficient magnitude that (b) may have resulted in some cases in concussions, so that they (c) may be monitored for signs of concussion or (d) may be asked to undergo a balance, vision, and/or neurocognitive test on the sidelines, the results of which (e) may suggest a removal from play for the remainder of the game and referral to a concussion specialist for formal evaluation away from the sports sideline, which (f) may result in a clinical diagnosis of concussion.
Answer: Yes, independent experts absolutely see benefits to using impact sensors now. Here are what they see as the major benefits:
Answer: Yes, a number of top concussion researchers also believe that real-time monitoring of impacts could help reduce the total amount of brain trauma from repeated subconcussive blows by identifying athletes sustaining a large number of such hits due to improper blocking or tackling technique. In a recent article on SI.com , Kevin Guskiewicz, PhD, ATC., Kenan Distinguished Professor and Director of the Matthew Gfeller Sport-Related Traumatic Brain Injury Research Center at The University of North Carolina at Chapel Hill, said sensors are helping coaches and other personnel at UNC identify athletes who are sustaining a high number of high force impacts, especially to the top front of their helmets that appear to be the most worrisome from a brain trauma standpoint, as a result of poor tackling or blocking technique. "If a player is observed repeatedly sustaining larger impacts to the crown of his head," he told SI, "coaches will work with him on adjusting his technique," said Guskiewicz.
Using impact sensors as a teaching tool isn't just happening at the college level. It is happening in high school football, too. After Purdue researchers  found that high school football linemen who sustained a high number of high impact sub-concussive hits over the course of a season were the ones suffering impairment of their visual memory, the information led at least one player to change his blocking technique.
As Tom Talavage, the lead author of the Purdue study, told Frontline in a 2011 interview , he thought at least 50 percent of the high impact hits linemen and linebackers were sustaining were due to poor technique. "Some of the players that we have on our team have not very good technique, to be quite honest. And what you'll find is, they will launch into a play, and they will lead with their helmet. Other players will more correctly keep their head up, try to get their arms up as a blocking technique, or when they're rushing, they will try to get their arms up as a means to push the offensive lineman out of the way. Those technique differences lead to a very large difference in the total number of blows experienced and where those blows are experienced on the head."
Talavage said that when one of the offensive lineman who was found to have been functionally impaired after sustaining a high number of subconcussive blows, impairment that persisted beyond the season, decided to change his technique, he experienced a drastic reduction in the number of blows he experienced to the top front of his head and a moderate reduction in the total number of blows.
The result was that, after the second season, "his neurocognitive testing never detected any deficits, and from an imaging perspective we saw substantially less change in his fMRI activity. There's still some, because he's still getting hit, but his technique changed the distribution."
Research suggests that the cumulative effect of subconcussive impacts increases the risk of long-term neurodegenerative diseases such as CTE, PD, AD, MCI and ALS. While researchers continue to look for the concussion "holy grail" in the form of specific impact thresholds above which concussions are highly likely and/or the number of impacts or the magnitude of impacts per week or per season that substantially increase the risk of long term brain injury, impact sensor technology is available right now to help reduce total brain trauma by using impact data to identify kids who need more coaching so they can learn how to tackle and block without using their helmets.
Answer: Absolutely. As with any emerging technology, there will be early adopters and late adopters. Not surprisingly, some concussion scientists and researchers take a more cautious approach to the use of impact sensors than others. Despite finding that underreporting continues to be what she wrote in two 2013 studies to be an "alarming" and "overwhelming" problem, Johna Register-Mihalik, Ph.D, LAT, ATC, Senior Research Associate at WakeMed and Adjunct Assistant Professor at UNC-Chapel Hill, recently told MomsTEAM that the reason she and her colleagues did not recommend the use of impact sensors in addressing the problem was that she viewed "the use of impact sensors in concussion detection, as the science, although a growing field of information, [as] just not quite there in [terms of] how the[y] may best be used from a clinical standpoint and across all sport settings."
Register-Mihalik recognized that "there is certainly potential for this type of technology to have great implications in the identification of concussion as the science advances," but, she argued, "we need more scientific and unbiased evidence of their ability to detect concussion before they are widely used and recommended in all settings. Until that time, there are some good examples of identification techniques of having trained observers, a parent advocate and continuing to promote concussion education that we know will increase identification rates."
Note, however, that Register-Mihalik was assuming that impact sensors would be used to diagnose concussions, which, as noted above, is not their intended use.
Answer: Yes, such a potential concern has been expressed by some concussion experts. They worry that sensors may identify individuals who receive a certain type of hit or impact, but that impacts not above the threshold may nevertheless lead to concussion, providing a false sense of security, in that "if the sensor didn't go off, I must not have a concussion."
The problems of false negatives (i.e. the sensor not going off when the athlete is later found to have suffered a concussion), and false positives (i.e. the sensor triggering an alert when the athlete is later found not to have suffered a concussion) are real concerns. Their effect can be minimized, however, if sideline personnel remember to always keep in mind that the sensors are not diagnostic and simply provide additional information for use by sideline personnel in identifying athletes for sideline screening and/or close observation.
Answer: It is true that there are, as of yet, no controlled studies showing that a team which adds impact sensors to its concussion toolbox helps sideline personnel do a better job of identifying concussed athletes than a team that relies on self-reporting by athletes and the observational skills of sideline personnel and game officials.
My own anecdotal experience so far, however, has been positive. While only a limited number of helmets of Newcastle football players were fitted with Shockbox sensors for the 2012 season we filmed for "The Smartest Team," the results, admittedly from a very small sample size, were very encouraging:
I am not a scientist, nor a biomechanical engineer. As such, I recognize and appreciate that there are some in the concussion community, especially scientists - who by their very nature are appropriately cautious in endorsing any new technology without validation via rigorous, peer-reviewed testing - and some helmet manufacturers who believe that impact sensor technology has not advanced sufficiently to warrant widespread use in contact and collision sports. Again, it appears that their objections rest largely on the assumption that they are going to be used to diagnose concussions, which is not their intended use.
My experience with the Newcastle football team in Oklahoma leads me to believe that, as long as impact sensors are strictly used for the limited purpose of providing real-time impact data to sideline personnel, not to diagnose concussions, not as the sole determining factor in making remove-from-play decisions, and not to replace the necessity for observers on the sports sideline trained in both the signs and symptoms of concussion and in conducting a sideline screening for concussion using one or more sideline assessment tests for concussion (e.g. SCAT3, balance, King-Devick, Maddocks, SAC)(preferably by a certified athletic trainer and/or team physician), they represent a valuable addition to a program's concussion toolbox.
Answer: That's a hard question to answer yes or no.
The short answer is that whether an after-market impact sensor manufactured by a third-party voids the NOCSAE warranty will depend on (a) whether it is affixed to the inside or outside of a helmet (some are, some are not); (b) whether the helmet manufacturer has decided that the impact sensor voids the NOCSAE certification; and (c) whether the impact sensor manufacturer has made their own certification of compliance with the NOCSAE standard on a helmet model.
The long answer is that, it is true that the National Operating Committee on Standards for Athletic Equipment (NOCSAE) initially decided  in July 2013 that modification of helmets with third-party after-market add-ons, such as impact sensors installed inside a helmet or to its exterior, would be viewed as voiding its certification, and that the certification could only be regained if the helmet was retested by the manufacturer with the add-on, it subsequently, NOCSAE issued a press release clarifying that position : Instead of automatically voiding the certification, NOCSAE decided it would leave it up to helmet manufacturers to decide whether a particular third-party add-on affixed to the helmet, such as a impact sensor, voided its certification, and now allows companies which make add-on products for football helmets to make their own certification of compliance with the NOCSAE standards on a helmet model, as long as the certification is done according to NOCSAE standards, and as long as the manufacturer assumes responsibility (in other words, potential legal liability) for the helmet/add-on combination.
An additional complicating factor for high school football programs is the question of whether a football helmet to which an impact sensor has been affixed violates the rules of the National Federation of State High School Associations (NFHS) or of a state high school athletic association. Article 1, Rule 1‐5.1.a. of NFHS's rule entitled "Mandatory equipment" states, in pertinent part, that a participating football player must "wear a properly fitted helmet ... which shall be professionally manufactured and not altered to decrease protection, ...[and] which met the NOCSAE test standard at the time of manufacture." (emphasis supplied).
A strict reading of that language would appear to allow a helmet to which a third-party, after-market product has been affixed so long as the alteration does not "decrease protection," and so long as the helmet met the NOCSAE test standard at the time it left the manufacturer. MomsTEAM has repeatedly requested that the NFHS clarify its interpretation of this rule in light of the NOCSAE statements but, as of October 10, 2013, the NFHS has not issued one.
I should also note that, when liability and warranty concerns were raised during the filming of "The Smartest Team" in the summer of 2012, both by the school's attorney and by Schutt, we moved swiftly to address them by having a Shockbox-equipped Schutt helmet drop-tested at Schutt's testing facility. When the testing showed that the insertion of the 3 1/2 ounce sensor in between sections of the interior padding of the Schutt helmet did not in any way effect its performance characteristics, Schutt was able to assure the school that the helmet modification did not void its warranty, and we were able to proceed. Similar arrangements have been put in place to allow even more players on the 2013 Newcastle football team to play with impact sensors this season.
Answer: In the final analysis, while NOCSAE has every right to protect the integrity of its standards, it should be up to market to determine winners and losers, with as little government or private interference in that process as possible, so that the best company with the best technology wins. That's called free enterprise.
Hopefully, the new NOCSAE ruling will not bring technological innovation to a screeching halt, and will be no more than a speed bump on the road to improved player safety.
In the meantime, we believe it should be up to schools, coaches, parents, athletic trainers, team doctors, and the athletes themselves to weigh the benefits and risks of impact sensors, and make the decision that is most likely to improve player safety, NOCSAE certification or no.
For an impact sensor buying guide, click here .
Questions or comments? Email Brooke at firstname.lastname@example.org
Posted October 11, 2013; most recently revised November 5, 2013