Sleep Stickies: Designing A Portable EEG Device For Children

Students standing in front of their project poster

Alycia Cheng, Elizabeth, Bhavita Jindal, Dainelle Morales, Kendall Mooney, Lindy Shi

Community Partner: Dr. Lyndia Wu, Department of Mechanical Engineering
Degree: Bachelor of Applied Science
Program:
- Mechanical Engineering
Campus: Vancouver

Our project

EEG (electroencephalography) devices are used to diagnose and monitor epilepsy, sleep disorders, brain injuries and other conditions. These devices often include more than 20 electrodes that are attached to the scalp to collect data while the patient spends the night at a hospital or sleep clinic. The long set-up time, combined with their use in away-from-home settings, makes it difficult to use these devices when working with patients who are children.

Our client, Dr. Lyndia Wu, asked us to design a child-friendly portable non-invasive EEG device that could be used by children in home environments.

We were encouraged to make the device as accessible as possible and to create a simple design and interface that would be easy to use and visually appealing.

Our design solution and process

We designed a lightweight single-channel three-electrode EEG system that can be set up in under 10 minutes, takes 1.5 hours to charge, collects data for just over 11 hours and can log 15 full nights of EEG data. The three electrodes snap on to an electrical case that houses our custom circuit. This is all enclosed in a custom silicone jacket that matches forehead curvature. The device is attached to the child’s forehead using standard medical adhesive.

To arrive at this solution, we did a lot of research and brainstorming sessions, looking into existing EEG devices as well as other medical technologies for inspiration.

We explored a variety of options for ensuring contact between the electrodes and the user, including sleep masks and full bands. While dry electrodes might be more comfortable for the user, they are more prone to shifting, which prevents accurate data measurement. Devices that adhere to the user are more likely to generate the data that health-care providers need to diagnose and monitor conditions.

In another avenue of research, we explored the optimum number of electrodes. While in-hospital devices use many electrodes, our tests determined that a three-electrode single-channel device could achieve comparable data quality.

The challenges we faced

One issue we faced was determining how to quantify some of the design criteria for this project. It was extremely important for our client that the device be comfortable, but determining how to quantify comfort was not straightforward. One of the primary qualities associated with comfort was not being able to perceive the device or have it negatively affect your sleep quality.

We developed a formula that incorporates user feedback and other variables, including the thickness of the device (a thicker device was more uncomfortable if you moved around while sleeping) and skin irritation.

As is often the case in the design cycle, we would come up with an idea that seemed promising, but as we advanced the initial premise new issues emerged. Each design decision had implications. Our early iterations – which were much bulkier or had a longer band – looked quite different from the finished product. We also faced some technical challenges when integrating the mechanical and electrical parts and encasing the electrical circuitry.

What we’re most proud of

This was a very rewarding project that encompasses the broad nature of mechanical engineering: our project integrates mechanical and electrical engineering as well as software functionality.

We enjoyed developing an initial idea through all of the design stages to a finished product.

When we began this project, we had little knowledge of EEG devices. Working as a team, we expanded our knowledge base, learned how to do quick iterations to test our design ideas, advanced our skills in CAD and 3D printing, and met all client requirements on time and on budget.

The group of us have been friends for four years and we’d wanted to work on a capstone project together. We’re pleased by our ability to bring together and apply the knowledge we’ve learned in our courses and to work together as a team that values the healthy and respectful exchange of ideas.

It has also been fun to work on a project that we can test on ourselves, and it’s been rewarding to work on a project that could ultimately have a positive impact on children with sleeping disorders or other conditions.

Our project’s future

The device we’ve developed is meant to be used in a research setting, rather than being commercialized and sold to market.

There are areas where it could be refined, including miniaturizing the electronic components to make it even less bulky. While our device can record brain waves and store data, it doesn’t analyze the data on sleep stages. Future iterations could incorporate machine learning algorithms to classify sleep stages and could connect the device to an app to enhance user interaction.