Flexible sensors could pave the way for safer sports helmets

March 17, 2021

New sensors might help helmets protect heads. (Pixabay/WikiImages)

Researchers have developed a new wearable sensor technology that could provide new insight into how helmets can fit better and more effectively protect athletes' brains during sports and other physical activities.

In a paper published Wednesday in ACS Sensors, a team of electrical engineers at Western Michigan University designed a set of 16 specially crafted sensors, constructed with electrodes made from silver ink, that monitor subtle interactions between a player's helmet and head. The sensors can wirelessly transmit data to a computer or other device in real time to precisely track the location and intensity of impacts to the head. 

Though it's well known that collisions can lead to concussions, how an athlete's helmet affects the equation is less understood. And since helmets are designed to absorb shock, an improper fit can lead to concussions and other serious head injuries — especially for high school athletes who sustain over 650 impacts in a single season, according to a study in Current Opinion in Pediatrics.

"More than the impact sustained in the field, if the helmet is not fitted properly, that is another major leading cause of head injuries," said Binu Narakathu, a research associate at Western Michigan University. Narakathu operates SafeSense Technologies, a private company that partners with the university to handle the commercial application of new engineering developments.

"It is a problem that has not been addressed," Massood Atashbar, a professor of electrical and computer engineering who headed the project, told The Academic Times. An improperly fitted helmet "can move the head and neck of the player in the wrong direction and cause many other injuries, in addition to traumatic brain injury and concussions."

The existing standard for helmet-fitting is imprecise at best, with trainers asking players for their subjective opinion about whether their helmets fit snugly. Some of these injuries would be prevented if coaches had tangible data to help guide fittings, Atashbar said.

The Western Michigan team noted that around 50% of concussions go underreported or are not reported at all. Between 1.6 and 3.8 million Americans face sports and recreation-related traumatic brain injuries each year, according to the Centers for Disease Control and Prevention.

The current study isn't the first attempt to track the effectiveness of helmets in protecting against traumatic brain injuries. But the sleeker design of the researchers' new sensors, with each electrode embedded into a thin sheet of cloth-like material, offers a less intrusive fit inside a player's helmet compared to previous models. After equipping around 10 helmets with the sensor arrays and then tracking local high schoolers during football practice, the engineers said their field tests into the sensors' construction and response times demonstrate the feasibility of eventually using the technology for medical purposes.

It's often difficult for physicians to identify the severity of traumatic brain injuries, which in some cases are undetectable by magnetic resonance imaging. But whereas older sensors struggled to track smaller, micro interactions between a helmet and a player's head, the team's latest sensors provide a more robust data set for physicians to spot how impacts lead to different injuries in the brain.

Since traumatic brain injuries often have long-term psychological and health effects, helmet manufacturers are working to find data that could help them construct customized helmets that fit more securely on athletes. SafeSense is sharing its data with Xenith Helmets and other companies that can incorporate the findings into new designs.

The engineers said their durable sensors differ from typical technologies that are often fragile, expensive and rigid. In the future, flexible sensors could be used for electroencephalogram and heart monitors, thermostats and eye augmentation. The sensor technology could also be useful for other sports where collisions are common, including cycling, ice hockey and boxing.

Besides its medical applications, coaches may appreciate the new technology for another reason: the data can also help them better analyze each player's performance on the field. 

A particular player "might have a style, which the coach might not notice with his bare eyes, because there are so many things happening in the field," Narakathu said. "Training is another area where this data will be really helpful."

The study, "Highly sensitive porous PDMS-based capacitive pressure sensors fabricated on fabric platform for wearable applications," published March 17 in ACS Sensors was authored by Simin Masihi, Massood Atashbar, Masoud Panahi, Dinesh Maddipatla, Anthony Hanson, Arnesh Bose, Sajjad Hajian, Valliammai Palaniappan, Binu Narakathu and Bradley Bazuin, Western Michigan University. 

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