Wearable, noninvasive monitor continuously tracks GI activity

By John Murphy, MDLinx
Published April 10, 2018

Key Takeaways

What the electrocardiogram does for the heart, a new monitor could do for the gut, predicted a team of engineers and physicians who developed a wearable, noninvasive device that continuously monitors electrical gastrointestinal (GI) activity. They described their results in a recent article in Scientific Reports.

The electrical gut monitor, as the developers call it, can track GI activity round-the-clock and in the wearer’s normal environment—a major difference from current systems that can be used only in the clinic. This device could lower the cost of testing, eliminate the invasive component, and expand the data-gathering window to include information on the circadian and sleep effects of GI disorders, the developers noted.

“This work opens the door [to] accurately monitoring the dynamic activity of the GI system,” said corresponding author Todd Coleman, PhD, MS, professor, Department of Bioengineering, University of California at San Diego (UCSD), La Jolla, CA. “Until now, it was quite challenging to accurately measure the electrical patterns of stomach activity in a continuous manner, outside of a clinical setting. From now on, we will be able to observe patterns and analyze them in both healthy and unwell people as they go about their daily lives.”

Personalized diagnoses

The device consists of a small box that houses an 8-channel amplifier, an SD card for data storage, a small battery, and an accelerometer for tracking the wearer’s movement. Attached to the box are 10 electrodes that are placed in a grid pattern on the wearer’s abdomen over the stomach. A smartphone app allows the user to log events or activities (meals, bowel movements, sleep/wake times, symptoms, etc.) in sync with the digital record of electrical GI activity.

The device improves on an existing method of noninvasive GI recording: the electrogastrogram. In their article, the developers explain that the electrogastrogram hasn’t been widely adopted for several reasons: its results don’t correlate well with other standard tests; it’s susceptible to noise and motion artifacts; it records only one channel; and it’s clinic-based, not wearable.

In comparison, the new device has an algorithm that filters out artifacts. It records eight channels of data and can be worn continuously for ambulatory use.

“We think our system will spark a new kind of medicine, where a gastroenterologist can quickly see where and when a part of the GI tract is showing abnormal rhythms and as a result make more accurate, faster, and personalized diagnoses,” said the paper’s first author Armen Gharibans, PhD, postdoctoral research fellow at UCSD.

Testing against the gold standard

In their study, the developers tested the wearable monitor against gastric manometry—the current clinical gold standard for assessing GI motility—in 11 children in the San Diego area. (The researchers recruited children because the only site in the area that performs gastric manometry is a pediatric hospital.)

Subjects were simultaneously monitored with the wearable device and with gastric manometry (an invasive procedure in which a catheter is inserted through the nose and positioned in the stomach). After making some adjustments to improve the device’s signal, the researchers demonstrated that the data recorded by the wearable monitor correlated closely to gastric activity.

“I have been practicing pediatric gastroenterology and taking care of patients for 20 years,” said Hayat Mousa, MD, director, Neurogastroenterology and Motility Center, Rady Children’s Hospital, San Diego, CA, who assisted with the study. “My challenge has always been finding a test that offers a noninvasive assessment of the enteric nervous system and its connection with brain function.”

Dr. Mousa, who is also a professor of pediatrics at UCSD School of Medicine, added, “The technique outlined in this paper is the best way to evaluate children with motility and functional GI disorders. It provides the information without need for sedation and it offers the flexibility to monitor kids while they continue their daily activities. This procedure allows convenience without compromising accuracy.”

In addition, the device could be used to monitor delayed gastric emptying in patients with diabetes and Parkinson’s disease, or heartburn and other GI problems in pregnant women and the elderly.

Still in development

The developers caution that the device needs more fine tuning before it’s ready for clinical use. The box could be miniaturized for improved wearability, for instance, and the number of electrodes could be increased for greater coverage. A new app could be designed to allow patients and physicians to see the GI activity data in real time. Importantly, it needs to be further validated in larger studies with more diverse study populations.

To learn more, visit the team’s website at gi2.ucsd.edu.

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