Will your smartphone be the next doctor’s office?

The same devices used to take selfies and type out tweets are being repurposed and commercialized for quick access to information needed for monitoring a patient’s health. A fingertip pressed against a phone’s camera lens can measure a heart rate. The microphone, kept by the bedside, can screen for sleep apnea. Even the speaker is being tapped, to monitor breathing using sonar technology.

In the best of this new world, the data is conveyed remotely to a medical professional for the convenience and comfort of the patient or, in some cases, to support a clinician without the need for costly hardware.

But using smartphones as diagnostic tools is a work in progress, experts say. Although doctors and their patients have found some real-world success in deploying the phone as a medical device, the overall potential remains unfulfilled and uncertain.

Smartphones come packed with sensors capable of monitoring a patient’s vital signs. They can help assess people for concussions, watch for atrial fibrillation, and conduct mental health wellness checks, to name the uses of a few nascent applications.

Companies and researchers eager to find medical applications for smartphone technology are tapping into modern phones’ built-in cameras and light sensors; microphones; accelerometers, which detect body movements; gyroscopes; and even speakers. The apps then use artificial intelligence software to analyze the collected sights and sounds to create an easy connection between patients and physicians. Earning potential and marketability are evidenced by the more than 350,000 digital health products available in app stores, according to a Grand View Research report.

“It’s very hard to put devices into the patient home or in the hospital, but everybody is just walking around with a cellphone that has a network connection,” said Dr. Andrew Gostine, CEO of the sensor network company Artisight.

Most Americans own a smartphone, including more than 60% of people 65 and over, an increase from just 13% a decade ago, according to the Pew Research Center. The COVID-19 pandemic also pushed people to become more comfortable with virtual care.

The applications even reach into disciplines such as optometry and mental health:

  • With the microphone, Canary Speech uses the same underlying technology as Amazon’s Alexa to analyze patients’ voices for mental health conditions. The software can integrate with telemedicine appointments and allow clinicians to screen for anxiety and depression using a library of vocal biomarkers and predictive analytics, said Henry O’Connell, the company’s CEO.
  • Australia-based ResApp Health got FDA clearance last year for its iPhone app that screens for moderate to severe obstructive sleep apnea by listening to breathing and snoring. SleepCheckRx, which will require a prescription, is minimally invasive compared with sleep studies currently used to diagnose sleep apnea. Those can cost thousands of dollars and require an array of tests.
  • Brightlamp’s Reflex app is a clinical decision support tool for helping manage concussions and vision rehabilitation, among other things. Using an iPad’s or iPhone’s camera, the mobile app measures how a person’s pupils react to changes in light. Through machine learning analysis, the imagery gives practitioners data points for evaluating patients. Brightlamp sells directly to health care providers and is being used in more than 230 clinics. Clinicians pay a $400 standard annual fee per account, which is currently not covered by insurance. The Department of Defense has an ongoing clinical trial using Reflex.

In some cases, such as with the Reflex app, the data is processed directly on the phone — rather than in the cloud, Brightlamp CEO Kurtis Sluss said. By processing everything on the device, the app avoids running into privacy issues, as streaming data elsewhere requires patient consent.

But algorithms need to be trained and tested by collecting reams of data, and that is an ongoing process.

Researchers, for example, have found that some computer vision applications, like heart rate or blood pressure monitoring, can be less accurate for darker skin. Studies are underway to find better solutions.

Small algorithm glitches can also produce false alarms and frighten patients enough to keep widespread adoption out of reach. For example, Apple’s new car-crash detection feature, available on both the latest iPhone and Apple Watch, was set off when people were riding roller coasters and automatically dialed 911.

“We’re not there yet,” said Dr. Eugene Yang, a professor of medicine at the University of Washington. “That’s the bottom line.”