SAN DIEGO, Calif. — You may soon be able to screen yourself for neurological conditions like dementia and ADHD using just a smartphone. All you would have to do is take a selfie — of your eyes. Researchers at the University of California, San Diego are developing a new app that uses eye recordings to assess cognitive health.
The app uses both a near-infrared camera (built into most new smartphones available today) and a “standard selfie camera” to track pupil size dilations. These pupil measurements can then help assess a person’s cognitive state, the study authors explain.
“While there is still a lot of work to be done, I am excited about the potential for using this technology to bring neurological screening out of clinical labs and into homes,” says study first author Colin Barry, Ph. .RE. student at UC San Diego, on a college field trip. “We hope this will open the door to further explorations of using smartphones to detect and monitor potential health issues earlier.”
Students provide insight into cognitive functioning. For example, when someone is thinking hard about a difficult mental task or hearing an unexpected loud sound, the pupils tend to dilate.
The app closely tracks changes in pupil diameter with a student response test. Researchers believe this eye selfie test can quickly screen and even monitor a number of neurological diseases and disorders.
How does the brain disease app work?
Normally, this test requires specialized and expensive equipment, which makes it difficult to perform consistently outside of a laboratory environment. Fortunately, engineers from the Digital Health Lab, led by UC San Diego professor of electrical and computer engineering Edward Wang, worked with researchers from the UC San Diego Mental Health Technology Center (MHTech Center ) to develop an affordable and easier way to administer the test.
“A scalable smartphone-based assessment tool that can be used for large-scale community screenings could facilitate the development of student response tests as minimally invasive and inexpensive tests to aid in the detection and understanding of diseases like Alzheimer’s disease. This could have a huge impact on public health,” adds Eric Granholm, professor of psychiatry at UC San Diego School of Medicine and director of the MHTech Center.
The app designed by the UC San Diego team uses smartphones’ near-infrared cameras to detect and track the student. In the near infrared spectrum, it is quite easy to differentiate the pupil from the iris, even in eyes with dark iris colors. Thus, the application is able to calculate the size of the pupil very precisely (down to sub-millimeter!) on many eye colors.
Additionally, the app uses a more traditional color image taken with the smartphone’s selfie camera to measure the stereoscopic distance between the smartphone and the user. The system then converts the pupil size of the near-infrared image into millimeter units.
The new “gold standard” in the palm of your hand?
It’s worth mentioning that the measurements taken by the app were comparable to those taken by a device called a pupillometer, which scientists consider the gold standard for measuring pupil size. The development team has also included a number of features intended to make the app more senior-friendly.
“For us, one of the most important factors in technology development is to ensure that these solutions are ultimately usable by everyone. This includes people like the elderly who might not be used to using smartphones,” says Barry.
The study authors worked directly with a group of seniors to design a simple app interface. Features include voice commands, image-based instructions, and an affordable plastic bezel to help direct the user’s eyes to the smartphone camera view.
“By testing directly with seniors, we’ve discovered ways to improve the overall usability of our system and have even helped innovate senior-specific solutions that allow people with different physical limitations to use our system. successfully,” Professor Wang concludes. “When developing technologies, we need to look beyond function as the sole measure of success, to understanding how our solutions will be used by a wide variety of end users.”
In the future, the researchers will continue their work on this project. Specifically, they are now turning their attention to enabling similar pupillometry features on older smartphone models. Future studies looking at self-screening for dementia in older adults are currently in the planning phase.
The team presented their findings at the ACM Computer Human Interaction conference on Human Factors in Computing Systems (CHI 2022).