A self-powered sensor neck patch has been developed to determine head kinematics — the angular acceleration and the angular velocity during collision — which could be used to detect concussions, according to a report published in Scientific Reports.
Neuropsychological changes, ranging from loss of memory to cognitive problems, and neurodegenerative diseases, such as chronic traumatic encephalopathy (CTE), are often present in athletes involved in high-contact sports. This is usually a consequence of traumatic brain injuries (TBIs) and repeated concussions. Current concussion-detection systems are accelerometer-based, thus relying on sensors in the helmet of an athlete, with no sensors attached directly to an athlete’s head. This excludes all athletes without helmets and can’t account for helmet sliding producing false readings.
A partial solution to helmet sliding was produced by X-Patch — a patch placed behind the ear or in the mouth guard that captures rotational speed. However, both resulted in significant errors measuring peak angular accelerations.
Research developers in this field have designed a device that uses a Ferro-Electret Nano-Generator (FENG) that generates a measurable electrical output (quasi-piezoelectricity). They used patches at the neck to describe tensile stress, which also produces an electrical output from each device. The relationship between the neck strain and the FENG’s output was used to develop an electrical pulse profile that was then correlated with the kinetic signature of a human head, resulting in a more reliable concussion-detection system. A dummy dropped head-first was used to test this system though with no direct collision to the head.
The patch (FENG device plus electrodes and tape to protect the electrodes) was attached at the back of the dummy’s neck. The fall resulted in applied tensile force to the patch, rotational displacements around the “y” axis, imitating a frontal auto-crash whiplash effect (hyperflexion and hyperextension) as well as the whiplash effect in high-contact sports.
Data from the patch was recorded and analyzed and confirmed by computer-based simulations revealing a strong linear correlation with the FENG’s output during hyperflexion. Peak angular velocity and acceleration can be determined (R2>90%) by the novel wearable sensor.
There is a positive correlation between the patch output and human-head rotational kinematic signatures, a result supported by computer modelling simulation. The FENG showed less than 10% variation in sensitivity.
Research developers added that “although this work demonstrates the system along one spatial axis, it can certainly be expanded along the other axes by placing multiple sensors around the neck; thus providing a full, comprehensive map of the human head during a collision.”
Dsouza H, Pastrana J, Figueroa J, Gonzalez-Afanador I, Davila-Montero BM, Sepúlveda N. Flexible, self-powered sensors for estimating human head kinematics relevant to concussions. Sci Rep. Published online June 23, 2022. doi:10.1038/s41598-022-12266-6