PORTLAND, Ore. -- Sports-related concussions have skyrocketed in the U.S. with over 3.8 million reported each year. New MEMS sensors small enough to be mounted inside an athlete's helmet, for example, could perform early detection of symptoms, giving doctors time to administer preventative therapies.
"Starting about a year and a half ago we started getting requests for MEMS accelerometers to detect concussions," said Wayne Meyer, MEMS marketing and applications manager at Analog Devices. "Concussive forces start at around 60 Gs and go up to about 120 Gs, but most applications also want to provide some headroom so the sensor never saturates,” Meyer added. “So we built ours to sense plus or minus 200 Gs."
Using high-G sensors for early detection of concussions could drastically reduce injuries, according to the American Association of Neurological Surgeons, since most injuries occur because treatment is delayed. More than 75 percent of concussions go undiagnosed, eventually contributing to over 30 percent of head trauma deaths in the U.S., according to the Centers for Disease Control and Prevention. Early detection also could cut medical bills and lost productivity, which is estimated to exceed $76 billion annually.
Analog Devices, which already produces single-axis, high-G accelerometers used to detect concussions in IndyCar drivers, recently redesigned their high-G sensor into a single chip, allowing it to fit inside football and other sports helmets. The high-G MEMS accelerometer measures 3-by-3-by-1.45 mm, making it small enough to fit inside a helmet-mounted earpiece to measure head trauma. The ADXL377 draws only about 300 microAmps, making it suitable of battery operation.
"There are many sports where high-G accelerometers could be used to detect concussions,” said Meyer. “Football and skateboarding come to mind immediately, but even cycling, water sports and snow skiing are all candidates.” Industrial and aerospace applications include high-G MEMS sensors used along with impact tools and other machinery, he said
Recent high-profile NFL incidents involving repeated head trauma have upped the ante for concussion detection solutions. For instance, after former NFL linebacker Junior Seau's recent suicide has been linked to possible head trauma over the course of a long career. Other former NFL players have joined in a lawsuit against the lead claiming it ignored the health and safety of players.
Apparently is up to individual players, according to TheProCap.com website. Here is one quote from there:
"As the first NFL player to wear one, I took a lot of ribbing from my teammates. 'Bubblehead' or 'Kazoo', as I was referred to, soon, learned that I could take and make hits without concussive side effects. Prior to ProCap I had numerous concussions. The ProCap extended my pro career by 5 years, including four Super Bowls,and I have a clear head in my life after football," said Mark Kelso (Buffalo Bills All-Pro Safety, 1985-1993).
You may be onto something there. That could definitely be tested too by comparing the outputs from the helmet-mounted and in-ear accelerometers for a soft outer shell. However, I suspect the answer is durability, since a soft outer shell might get damaged more easily.
I have a question. Why not put energy absorbing material on the outside of the helmet? It would greatly reduce energy transfer during helmet hits while still allowing full movement and vision. Or am I missing something. I played football in high school and it just occurred to me that there was no reason for the helmet to have a hard outer surface.
The NFL has been talking to the IndyCar guys about adapting their design for an in-ear accelerometer that would go inside the football players ear, like ear plugs, instead on on the helmets. (You can't get accurate head trauma measurements by putting it on the helmet, says IndyCar, because the padding inside the helmet is designed not to transfer shock):
IndyCar says NFL rejected their current earpiece design for use in football, because it was too big and power hungry. But within a couple months, IndyCar plans to have a much smaller earpiece designed using ADI's single-chip three-axis accelerometer discussed above, which will be small enough for NFL plus can be battery powered since it uses 15-times less power. For testing helmets, it will also be useful to put a high-G accelerometer on both the helmet and in the ear canal, then you can evaluate different padding arrangements in the helmet and directly measure which is better by comparing the accelerometer outputs from the helmet-mounted and in-ear mounted accelerometers.
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