Ingestible Capsule Detects Sleep Apnea and Breathing Issues

Traditionally, identifying sleep disorders like sleep apnea involves patients spending an entire night in a specialized sleep laboratory, connected to numerous sensors and monitoring equipment. Scientists from MIT, Celero Systems, and West Virginia University are pioneering a far less invasive alter

Traditionally, identifying sleep disorders like sleep apnea involves patients spending an entire night in a specialized sleep laboratory, connected to numerous sensors and monitoring equipment. Scientists from MIT, Celero Systems, and West Virginia University are pioneering a far less invasive alternative: an innovative ingestible capsule designed to track essential vital signs directly from inside the patient's gastrointestinal tract.

This compact capsule, roughly the size of a standard multivitamin, incorporates an accelerometer to precisely gauge the individual's breathing rate and heart rate. Beyond its application in sleep apnea diagnosis, the researchers highlight its potential for identifying opioid overdoses among vulnerable populations.

Giovanni Traverso, an associate professor of mechanical engineering at MIT and a gastroenterologist at Brigham and Women's Hospital, describes it as "an exciting intervention to help people be diagnosed and then receive the appropriate treatment if they suffer from obstructive sleep apnea." He further notes, "The device also has the potential for early detection of changes in respiratory status, whether it's a result of opiates or other conditions that could be monitored, like asthma or chronic obstructive pulmonary disease (COPD)."

In a clinical study involving 10 human volunteers, the team demonstrated that the capsule effectively monitors vital signs and identifies sleep apnea events, characterized by repeated pauses and restarts in breathing during sleep. Importantly, none of the participants experienced any negative side effects, as the capsule passed through the digestive system without incident.

Traverso served as one of the senior authors on the study, alongside Robert Langer, an MIT Institute Professor and member of MIT's Koch Institute for Integrative Cancer Research; Victor Finomore, director of the Human Performance and Applied Neuroscience Research Center at the West Virginia University School of Medicine; and Ali Rezai, director of the Rockefeller Neuroscience Institute at the West Virginia University School of Medicine. The findings were published today in the journal Device.

Vital Sign Monitoring Capabilities

Over the last ten years, Traverso and Langer have pioneered various ingestible sensors aimed at tracking vital signs and diagnosing gastrointestinal conditions, including slowed gut motility and inflammatory bowel diseases.

This particular research centered on vital sign detection using a capsule engineered by Celero Systems. The device features an accelerometer sensitive enough to pick up subtle movements caused by the heart's contractions and the lungs' expansions. It is also equipped with two miniature batteries and a wireless antenna that relays data to an external receiver, such as a laptop computer.

Initial testing in animal models revealed that the capsule delivers highly accurate readings of both breathing rate and heart rate. In a notable experiment, it successfully identified a significant slowdown in breathing induced by a substantial dose of fentanyl, a potent opioid medication.

Encouraged by these preclinical outcomes, the researchers advanced to a human clinical trial conducted at the West Virginia University Rockefeller Neuroscience Institute. Ten enrolled patients were outfitted with the ingestible capsule while simultaneously being monitored via conventional sleep study sensors, enabling direct comparisons between the two methods.

The results confirmed that the capsule provided precise measurements of breathing and heart rates. Moreover, it reliably detected a sleep apnea episode in one participant, validating its diagnostic accuracy.

Traverso explains, "What we were able to show is that using the capsule, we could capture data that matched what the traditional transdermal sensors would capture." He adds, "We also observed that the capsule could detect apnea, and that was confirmed with standard monitoring systems that are available in the sleep lab."

During this trial, the team focused on signals from the capsule while it resided in the stomach. However, prior research by the group has established that vital signs can be reliably assessed from various other segments of the GI tract as well.

Traverso elaborates, "The stomach generally offers some of the best signals, mainly because it's close to the heart and the lungs, but we know that we can also sense them elsewhere."

All participants reported no discomfort or adverse reactions to the capsule. Follow-up radiographic scans conducted 14 days post-ingestion confirmed that every capsule had fully exited the body. The team's earlier studies indicate that similarly sized objects typically traverse the digestive tract in just over a day.

Applications for Continuous Monitoring

The researchers foresee this sensor transforming sleep apnea diagnosis by eliminating the need for cumbersome skin-attached devices currently in use. It could also play a key role in overseeing treatment initiation for apnea patients, ensuring therapeutic efficacy over time.

Celero Systems, co-founded by Traverso, Langer, Jeremy Ruskin—a professor of medicine at Harvard Medical School—and Benjamin Pless, the company's current CEO, is actively developing advanced versions of these sensors tailored for sleep apnea detection and opioid overdose prevention.

Traverso emphasizes, "We know that people who have had an overdose are at higher risk of recurrence, so those individuals could be monitored more closely so that in the event of another overdose, someone could help them."

Looking ahead, the team plans to integrate overdose reversal agents, such as nalmefene, directly into the capsule. This would enable automatic drug release in response to detected drops in breathing rate or complete cessation. Additionally, they are exploring techniques to extend the capsule's dwell time within the stomach for prolonged monitoring.

Funding for this research came from the Karl van Tassel Career Professorship, MIT's Department of Mechanical Engineering, and Celero Systems.

Additional authors on the paper include Pless, James Mahoney, Justin Kupec, Robert Stansbury, Daniel Bacher, Shannon Schuetz, and Alison Hayward.