SOURCE: X2 Biosystems

Richmond Public Relations

March 19, 2015 08:00 ET

X2 Biosystems Hails Concussion Studies With Several Sports Medicine Researchers

Results Showcase Advances in Concussion Management and Risk Assessment Enabled by X2's Head-Mounted Impact Sensor Technology

SEATTLE, WA--(Marketwired - March 19, 2015) - X2 Biosystems, a Seattle and Silicon Valley based provider of integrated solutions for the monitoring and management of concussions and other brain injuries in sports, military, and industrial environments, today hailed five complementary studies that showcase recent advances in concussion management and risk assessment enabled by the company's head-mounted impact sensor technologies.

The first study, entitled "Six degree of freedom (6DOF) measurements of human mild traumatic brain injury," was published by a team from Stanford University's Departments of Mechanical Engineering, Bioengineering, Medicine, Neurology, and Neurosurgery, together with researchers from the Department of Neuronic Engineering at the KTH Royal Institute of Technology in Stockholm. The three-year study (2011-2014) was supported by X2 with over $300,000 in impact sensor prototypes, test equipment loans, and engineering support. The results were published in the December 24, 2014 online edition of the Annals of Biomedical Engineering:, providing a detailed evaluation of the accuracy and performance of X2's pioneering six-degree-of-freedom (6DOF) impact sensor design, first introduced in 2010.

The X2 sensors were incorporated into custom-designed research mouth guards that in turn were deployed in Stanford athletics and Silicon Valley boxing and mixed martial arts clubs. The Stanford studies combined real-time impact sensor measurements and high-speed video recordings during live athletic events with finite element models of the compressive, tensile, and rotational shear forces generated in the brain by the observed impacts. The results suggest that the 6DOF data delivered by X2's impact sensor designs, which integrate miniaturized accelerometers and gyroscopes in order to measure both linear motion of the head (how fast the head is accelerating or decelerating in a single direction) and rotational motion of the head (how fast the head is turning), are a key component required to enable accurate real-time predictions of concussion injury risks caused by direct and indirect head impacts. The small sample size of athletes who experienced concussions in the Stanford study also suggests that further research is needed. 

Since 2010, X2 has incorporated the company's core 6DOF sensor technology into a variety of impact measurement device designs, including mouthguards and skin patches, to investigate the accuracy with which they measure the direction and severity of linear and rotational motion, since this combination is now known to play a key role in concussions. The Stanford studies have helped X2 to validate the importance of designing devices that ensure tight coupling to the skull. X2 has launched similar collaborations in 2015 to study the performance and enhance the usability of the company's next-generation head-mounted impact sensors.

The second study, entitled "Instrumented Mouthguard Acceleration Analyses for Head Impacts in Amateur Rugby Union Players over a Season of Matches", was published by a team from Auckland University of Technology (AUT), New Zealand, in the December 20, 2014 online issue of the American Journal of Sports Medicine:

The one year study revealed that the numbers and magnitudes of head impacts in amateur rugby union players over a season of matches, measured via X2's 6DOF impact sensors embedded in prototype "XGuard" mouth guards, were higher than those previously reported for most other sports. While the average linear accelerations measured over a season of matches were similar to those previously reported for youth, high school, and collegiate American football players, the average rotational accelerations (often implicated in more serous concussion injuries) were observed to be lower in rugby union players than those previously reported for American collegiate and professional American football players. This latter finding may support observations that the use of helmets in American football is correlated with a higher incidence of more violent impacts.

The third study, carried out by the US Army Aeromedical Research Laboratory (USAARL), studied X2's first generation skin-affixed "XPatch" impact sensors utilizing an experimental design similar to that used in many athletic and industrial equipment testing labs. Impacts were collected for the head-mounted sensors at multiple head impact sites and at different speeds using spring-mounted rubber head models on a linear impact sled. Peak linear and rotational accelerations and impact directions were compared to reference sensors embedded inside the rubber head models. Linear and angular accelerations measured by the skin-affixed impact sensors were found to correlate very well with the reference sensors embedded inside the head model. The study concluded that the XPatch system (software and sensor) was one of the most consistent environmental sensors for all of the laboratory tests, able to accurately record and store linear acceleration along three axes and rotation about three axes from impact events exceeding a designated trigger threshold. 

The fourth study was carried out by the Datalys Center for Sports Injury Research and Prevention in 2014, and commissioned by USA Football to evaluate injury reduction among youth football players in leagues that participate in USA Football's Heads Up Football® program. Results of the study were released in February 2015:

One component of the Datalys study measured and recorded contact to the head for 72 players 9-15 years of age using X2's first generation skin-affixed "XPatch" impact sensors. Of these 72 players, 38 were in Heads Up Football-participating leagues and 34 were in leagues not participating in the program. Youth players in leagues that had adopted Heads Up Football registered an average of 2.5 fewer impacts per practice of at least 10g. During a 12-week season with three practices per week, this would equate to a youth player in a Heads Up Football league receiving 90 fewer head impacts than one in a non-Heads Up Football league. The Datalys study also found that youth football players in Heads Up Football® programs had a 76 percent reduction in injuries compared to those in leagues that did not take part in the program. Such significant reductions in both head impacts and injuries are a compelling demonstration of the positive impact that coach and player behavior can have on player safety, and suggest that coach education programs like Heads Up Football® may serve as a model for a variety of youth sports concerned with concussion and head impact risk, such as soccer, ice hockey, lacrosse, and others.

The fifth study encompassed a group of research projects carried out in 2014 for which initial results were presented at the Virginia Tech 2015 Symposium on Head Acceleration Measurement Sensors on March 10, 2015. These projects all utilized prototype "Xguard" mouth guards and/or "Xpatch" impact sensors provided by X2 in 2014 to researchers at MEA Forensic Engineers & Scientists, the School of Kinesiology at the University of British Columbia in Canada, the Matthew A. Gfeller Sport-Related Traumatic Brain Injury Research Center / Department of Exercise and Sport Science / Injury Prevention Research Center at the University of North Carolina at Chapel Hill, Virginia Tech, Duke University, and Stanford University. Two key goals of these projects were to assess the relative accuracy of head-mounted vs. helmet-mounted impact sensors, and to examine usability challenges faced during lab testing and field deployment of head-mounted impact sensors. Although head-mounted and helmet-mounted devices were both shown to correctly detect ~96% of impacts, significant differences were observed in the projected head impact directions and magnitudes.

The results confirm observations by many other groups that head impacts can result in very different motions of an athlete's helmet versus the brain itself inside the skull inside the athlete's helmet. From a usability standpoint, these studies revealed that researchers often failed to record the precise orientation of the impact sensors, which can vary significantly due to lateral distortion and vertical rotation of mouth guards as a function of an athlete's (or rubber head model's) jaw shape, width, and tooth geometry, or as a function of skin patch mounting location and rotational orientation behind an athlete's ear. Failure to incorporate these details into impact analyses leads to a variety of errors, particularly in the reported impact directions. The studies also highlighted the need to account for vibrations in skin-mounted sensors caused by the motion of soft tissue during head impacts, which X2 and partners have studied in detail using both high-speed video and analyses of vibrational signals measured by the X2 sensors themselves. As an athlete's skin stretches and snaps back like a spring, it generates additional rapid accelerations that are recorded by the sensor. Failure to correct for these spurious accelerations leads to errors in both the reported directions and magnitudes of impacts, and these errors vary significantly with the location and direction of the original impact. 

X2 CEO John Ralston commented on the recent flurry of studies: "The large number and variety of studies that X2 has seeded with "Xguard" and "Xpatch" device prototypes showcase our commitment to and leadership in developing, testing, and refining industry-leading head-mounted sensor systems for concussion management and risk assessment. The results that all of these partners have shared with us have been invaluable in designing our next generation sensor products and concussion management solutions, being introduced in 2015, with accuracy, sensitivity, robustness, portability, simplicity, and ease-of-use that are ideal for athletes at all levels, as well as soldiers who are dealing with daily missions that may include extreme conditions and situations." 

About X2 Biosystems
X2 Biosystems ( pioneered the development of integrated biometric solutions to monitor and manage concussions and other brain injuries in sports, military, and industrial environments, and today serves customers that include professional, college, high school, and club athletic teams, military organizations, and leading sports medicine and clinical neurology organizations. X2's platform combines high-performance wearable impact sensors; tablet, smartphone, and PC software apps; and software-as-a-service applications, enabling training personal and physicians to collaborate with athletes, soldiers, and industrial users to deliver the best possible concussion care and recovery.

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