Non-invasive, Next-generation Systems for Diagnosis of Gastrointestinal Motility Disorders

Gastrointestinal motility disorders, such as gastroparesis, chronic constipation, irritable bowel syndrome and achalasia, hinder the normal movement of food, liquids and waste through the digestive system due to malfunctioning nerves or muscles. They represent a significant global burden affecting more than 10 percent of the world’s population. These conditions disrupt patients’ lives, but treatment methods such as wireless motility capsules (WMCs) — non-radioactive, ingestible devices used for diagnosing and treating gastrointestinal motility disorders — offer a significant improvement over previously used methods for measuring gastrointestinal transit.

Dr. Eamonn Martin Quigley, David M. Underwood Chair of Medicine in Digestive Health, published a study comparing and evaluating two WMCs – the Atmo Capsule and the SmartPill Capsule – for measuring gastric emptying time (GET) and colonic transit time (CTT) in patients with confirmed or suspected disordered gastrointestinal transit. Because the performance characteristics of the two WMCs were equivalent, the Atmo Capsule was found to be a valid method for evaluating gastrointestinal transit. The study was published in Clinical Gastroenterology and Hepatology.

 “The Atmo Capsule offers a suitable method for assessing regional and whole gastrointestinal transit, providing clinicians with a validated alternative wireless motility capsule to facilitate diagnosis of motility disorders,” says Dr. Quigley.

Benefits of wireless motility capsules

WMCs offer a significant improvement over previously used methods to measure gastrointestinal transit. Traditionally, gastric emptying scintigraphy and radiopaque marker testing were used to diagnose gastroparesis and slow transit constipation, respectively. However, these methodologies require separate healthcare visits for each test, are limited by a lack of standardization and entail radiation exposure.

WMCs enable a more comprehensive assessment of regional (i.e., each part of the gut) and whole-gut transit with a single, ambulatory, non-invasive study, which does not involve radiation exposure. This is important because many motility disorders involve more than one part of the gut; for example, gastroparesis and slow colonic transit commonly co-occur.

Wireless motility systems in gastrointestinal transit assessment

The Atmo Capsule, designed by Atmo Biosciences, is an ingestible device that measures levels of hydrogen (H₂), carbon dioxide (CO₂), oxygen (O₂) and temperature through the gastrointestinal tract as it moves from the esophagus to the rectum. The SmartPill motility system, developed by Medtronic, also includes an ingestible device that measures pressure, pH and temperature to calculate GET and whole-gut transit. Considered the gold standard, the SmartPill was discontinued in 2023, leaving a significant void in motility testing. Other technologies, such as the NaviCam from AnX Robotica, are also emerging to fill this market void.

According to Dr. Quigley, “With the discontinuation of the SmartPill Capsule, we now have a deficit in our diagnostic tools for the assessment of gut motility. The data presented in this study indicate that the Atmo Capsule may serve as a clinically useful and viable method of evaluating gastrointestinal transit. Currently, the Atmo Capsule is available on the market. Insurance companies are evaluating it for reimbursement, and I’m confident that it will be approved by several. And, it will find a place in the management of patients with gastrointestinal motility disorders.”

The Atmo Capsule received approval from the Food and Drug Administration (FDA) in June 2025.

Prospective study comparing the Atmo Capsule with the SmartPill Capsule

Pilot studies have demonstrated agreement between the Atmo Capsule and the SmartPill Capsule in assessing gastrointestinal transit. This study was undertaken at 11 academic and community centers in the U.S. and one in Australia from 2023 to 2024; however, it provides a much more robust comparison of the two technologies. Houston Methodist was one of the academic centers that participated. Study participants were 22 or older, and inclusion criteria included delayed GET from a previous study in the past two years, gastroparesis symptoms, functional constipation and constipation-predominant irritable bowel syndrome. Participants were excluded if there was evidence or suspicion of another gastrointestinal disease within the past six months that could explain the patients’ symptoms.

Two hundred thirteen participants enrolled in the study. Of that number, 209 ingested the capsules simultaneously. They fasted for 6 hours after capsule ingestion, remained on their normal diets, and wore receivers that detected radiofrequency signals emitted by the capsules. Receivers were worn continuously from the time of capsule ingestion until body exit, unless specified otherwise by the instructors.

The study measured the following:

• GET – time between ingestion to gastroduodenal junction (GDJ)

• SBTT (small bowel transit time) – time between the GDJ and ileocecal junction (ICJ)

• CTT – time between ICJ and body exit

• OCTT (orocecal transit time) – time between ingestion and ICJ

• SLBTT (small and large bowel transit time) – time between GDJ and body exit

• WGTT (whole gut transit time) – time between ingestion and body exit

The study concluded that the Atmo Capsule provides reliable measurements of GET and CTT that correlate with those from the SmartPill Capsule. There was, however, no agreement on the diagnosis of rapid transit times.

Both devices were able to identify the transition from the stomach to the duodenum and from the small intestine to the colon. Body exit was detected more frequently with the Atmo Capsule.

The study noted 148 adverse events related to capsule retention, abdominal pain and headache.

“A strength of this study was the simultaneous ingestion of the devices, particularly in relation to the measurement of gastric emptying time, with the mechanism of their emptying from the stomach applicable to both devices. Thus, in contrast to gastric emptying scintigraphy, which is based on the emptying rate of a mixed meal, emptying of a solid particle, such as a wireless motility device, has to await the resumption of a fasting motor pattern. Furthermore, the ingestion of the devices in tandem enabled control of factors shown to impact transit time, such as re-test variations and external factors, including variations in diet, the impact of stress, and psychological state. Finally, despite the limitations of device battery life impacting the evaluable dataset for analysis of colonic transit time, the calculated sample size target was met, along with the target for analysis of gastric emptying time,” Dr. Quigley added.

The objective, real-time data from the Atmo Capsule are used to diagnose motility disorders such as gastroparesis and constipation. In the future, it may revolutionize early detection and reshape how clinicians approach digestive health.

Braden Kuo, Allen A Lee, Thomas Abell, Ashok Attaluri, Michael Cline, William Hasler, Vincent Ho, Anthony J Lembo, Amir Masoud, Richard McCallum, Baharak Moshiree, Eamonn M M Quigley, Satish S C Rao, Abigail Stocker, Mayra Sanchez, Irene Sarosiek, Brian Surjanhata, Jerry Zhou, William D Chey. The Assessment of Gastrointestinal Transit by the Atmo Capsule: A Comparison With the SmartPill Capsule. Clin Gastroenterol Hepatol. 2025 Aug;23(9):1633-1641.e8. doi: 10.1016/j.cgh.2024.12.013.