Smart Mouthguard: Bio-analytics for the development of a respiratory sensing device

Injuries during sports participation are often caused by systemic failure due to physical exertion. Breathing parameters can be used to measure changes in perceived exertion allowing the athlete to monitor and check how they train or play the game. A smart mouthguard is being developed that incorporates a novel breathing technology to assess and track performance. It measures breathing, which can be analysed using model based analytics to estimate physical fatigue. The metrics will aid contact sport athletes in understanding their performance and assist in personalising their training regime without the requirement to wear any additional gear. It can also be used to make decisions regarding the potential injury risk athletes face during training or competition. This is particular relevant as more sport federations are making mouthguard use compulsory for all participants, while at the same time aiming to reduce overall injurie rates due to contact sport participation.

As athletic participation continues to increase around the world, the need for mouthguards will continue to climb. It has been estimated that over 40 million mouthguards are sold annually in the US alone. This number is expected to grow proportional with the increase of contact sport athletes. There is a strong need within the contact sports community to show that these sports can be played safely, as contact sports include some of the fastest growing sports in the world.

Accurate breathing analysis is required in order to provide good estimates of physical fatigue. The breathing signal is noisy and can vary widely between people. A computational model of the breathing signal reduces this noise and allows for better estimates of physical exertion. The University of Oxford with its expertise in bio-analytics will work together with Chiaro Ltd to develop a robust approach for tracking fatigue using a smart mouthguard. The project will consist of sharing knowledge on the best analytical modelling techniques and hardware designs to develop a user friendly smart mouthguard. The developed analytical model is tested using lab-based data and model modifications are made before applying it to field testing. The project shows how certain analytical techniques developed within other BBSRC's funded projects can successfully be translated to other industries.

The creation of a smart mouthguard consist of an initial assembly of optimised hardware components. Circuitry design will evolve from breadboard and perfboard to Gerber files for printed circuit board (PCB) manufacturing. A Bluetooth enabled microphone module forms the communication bridge between the smart mouthguard and an Android application. The final circuitry will be embedded in a customised mouthguard design that is constructed using injection molding. The yield and ultimate strength of the design will be tested with a digital force gauge. We will also be looking at the liquid ingress protection as described by IEC standard 60529 to determine that the system is fully waterproof. A small batch of 10 functional smart mouthguards will be manufactured. The interchanger will work with the electronic, industrial and mobile design engineers at Chiaro Ltd who will support the swift progression of this phase.

The smart mouthguard will generate Waveform Audio File Formats (WAVEs) to provide a high dimensional representation of the breathing patterns. Data analysis will consist of the exploration of several techniques, such as wavelet analysis and Graphical Models, which can be applied to deal with noisy physiological data. The analytical models are explored using a repeated testing methodology in which measured exertion on a BORG scale is used as a reference value for preliminary validation. These validation trials will consist of providing users with the manufactured batch of smart mouthguards and dedicated phones for data collection. Users will be asked to complete a functional short-term fatigue Protocol, both within the lab and on the field. The final model selection will be based on the initial lab-based testing and subsequent field testing outcomes.

Currently, no product exists for the contact-sport market that allows for reliable and comfortable performance measurements and which can greatly increase safe participation of athletes in a wide range of sports without the need for recalibration. Unlike pedometer and accelerometer devices the smart mouthguard makes direct physiological system measurements to determine the perceived intensity of exercise. This is supported by an almost perfect relationship between respiratory frequency and perceived exertion. In addition, breathing monitoring is perfect for measuring recovery and providing an estimate of overall fitness. More importantly, changes in ventilation alter the perception of exertion, while this is not the case with e.g. heart rate. The impact on the sports field of measuring breathing patterns for estimating exertion should be greater than the aforementioned technologies. Currently, an estimated one in five non-fatal unintentional injuries in young people is the result of sport or recreational activity. The promise to prevent injuries during (contact) participation will have a positive benefit on the lifelong health of those participating in these sports.

Broad adaption of the smart mouthguard makes it possible to identify best training trends and prevention methods, which would revolutionise how athletic populations are managed. This focus on wellbeing for sport participation is essential, as more and more people rely on sport activity to keep themselves physically healthy. Safe sport participation reduces the need for medical and social intervention throughout the lifespan of people. It will also further strengthen the UK's position as a leader in wearable technology.

The partnership with Chiaro Ltd described in the FLIP proposal provides a realistic and fitting collaboration for the proposed work. Interest has already been generated and we attended an Innovate UK, invitation-only event for Wearable Technologies presenting the smart mouthguard concept. Intel has contacted us in response to that event in order to discuss showcasing the capabilities of their newly developed Curie chip by placing it into the smart mouthguard. This is an early indicator of the impact this work can have on other connected industries.

This project will demonstrate how basic science developed in the BBSRC's funded "iBrain" project can generate broad impacts beyond the key goal of engineering a biological neural network. The interdisciplinary nature of the project and combination of skills makes this an ideal training opportunity for all those involved. The interchanger will benefit greatly from this project, as it will help to further establish himself within the field of wearable technology.

The University of Oxford is highly skilled in publicising research outcomes and there is no doubt that the smart mouthguard will cause curiosity globally, due to the real-world applicability of this FLIP project and the partners involved.