Brian Lacy, MD, PhD: Rethinking Motility Testing with a Noninvasive Wireless Patch System

Brian Lacy, MD, PhD

Credit: Mayo Clinic

New research is calling attention to the potential value of a wireless motility patch system for capturing multiday colonic myoelectrical activity, allowing for the noninvasive assessment of diurnal patterns of the entire GI tract.

Findings from the study were reported in a poster presentation at the American College of Gastroenterology (ACG) 2024 Annual Scientific Meeting in Philadelphia, Pennsylvania, and showed higher nighttime activity correlated with more frequent reports of “satisfactory” bowel movements.

Acknowledging limitations to current motility measurements, Brian Lacy, MD, PhD, of the Mayo Clinic in Jacksonville, and colleagues recognized the need for alternatives that are not invasive, are not restricted to a single organ, do not involve radiation exposure, and allow for the global evaluation of GI function.

Study results presented at ACG included 37 adult patients referred for a 4-hour, solid-phase gastric emptying scintigraphy who wore 3 wireless motility patches for 6 days while recording meals and bowel movements using an iPhone app. These patients had ≥ 2 days of recording (mean 4.9 days). Investigators observed 2 types of colonic activity: those with and without visible nighttime clusters in the colonic 12-28cpm range. A night-to-day ratio of 2 served as the cut-off for grouping into type H (high; > 2) and type L (low; < 2).

Average peak spectrums and corresponding boxplots showed lower daytime activity for both groups compared to the nighttime, with slightly elevated daytime colonic activity for type L compared to type H. Investigators noted nighttime activity was significantly higher for the type H group compared to type L.

In total, 26 patients recorded bowel movement events in the app, with 17 patients reporting predominantly “satisfactory” bowel movements and 9 patients reporting predominantly “unsatisfactory” bowel movements. Of note, 77% of individuals in the type H group reported predominantly “satisfactory” bowel movements compared with 45% in the type L group.

For additional insight into the limitations of current motility measurements and the potential utility of a wireless motility patch system, the editorial team of HCPLive Gastroenterology spoke with Lacy in the following Q&A:

HCPLive: Can you explain some of the limitations of current motility measurements like high-resolution manometry or gastric emptying scintigraphy?

Lacy: Gastric emptying scintigraphy is typically performed using a low-fat, low-volume meal. When performed properly, over 4 hours it provides information about stomach emptying in the moment. However, gastric emptying scans provide only a brief “snapshot” of gastric motor function during that 4-hour study that may not accurately represent the real-world setting.

The test meal is very low in fat, much lower than most people eat during any meal. It is also small in size, smaller than many patients ingest at home or while eating out. Also, although generally safe, the test meal does contain a small amount of radioactive material and thus should not be performed in children, pregnant women, or those who are breastfeeding, and because the meal contains eggs, it can’t be given to those with egg allergies. More importantly, we found that most centers across the United States don’t perform gastric emptying scans properly, and the data may not be accurate.

This all highlights that, although gastric emptying scans are commonly performed, we need to be cautious about interpreting the data from this very limited window of time, as it may not accurately reflect what is really going on with the patient.

Additionally, high-resolution colonic manometry can measure myoelectrical activity of the colon but is performed at only a few specialized centers in the United States. It requires a colonoscopy or sigmoidoscopy to place the catheter accurately. Many patients do not like the invasive nature of the procedure, although it can provide valuable information in patients with severe constipation.

HCPLive: How might real-world, noninvasive multiday testing help uncover new insights within the diurnal patterns of the entire GI tract? How was this explored through the wireless motility patch system in this study?

Lacy: An ambulatory test is likely to provide more useful information in the real-world setting than a test with a very small, low-fat meal. The ambulatory aspect allows patients to eat their typical meals at home or eat out while recording symptoms. Many patients note that they do not have any symptoms with the meal provided for gastric scintigraphy, but they have symptoms at home or while eating out.

Just as importantly, multiday testing allows symptoms to be captured over several days, not just in the moment of a 4-hour test. Not everyone with gastric motor and sensory disorders has symptoms every day. Increasing the testing period from 4 hours to 6 days provides a more accurate representation of gastric physiology.

Of note, we have learned that 48 hours of pH recording from the esophagus is better than 24 hours. I believe that the ambulatory nature of the wireless patch system showcases that same principle.

Regarding the diurnal nature of symptoms, classic teaching, based on colon motility studies (colonic manometry), was that the colon was generally very quiet – quiescent – at night, and then became more active in the morning – around 5-6 am for most people. However, this study contradicts that historical view as the wireless patch system showed that the colon is much more active at night than we previously thought.

Importantly, patients with predominant satisfactory bowel movements had higher nighttime activity than patients with unsatisfactory bowel habits. This finding may change how we treat patients with chronic constipation; using medications at night may help stimulate colonic motor activity overnight, leading to a more satisfactory bowel movement the following morning.

HCPLive: What were some of the key findings, and what do they suggest about the potential value of wireless motility monitoring?

Lacy: I think there were several key points worth emphasizing. One, patients found the patches easy to use and were very good about reporting symptoms on their smartphones. No special training or equipment (other than the patches) is needed. This means that it should be easy to use in any type of healthcare setting.

Two, the wireless patch system provided a wealth of novel information that will not just make us change how we think about colon motor activity, but also translate into changes in therapy. Lastly, testing of the colon with colonic manometry is rarely performed, thus limiting our ability to help patients better understand their symptoms and change their treatment. A safe and easy-to-use wireless patch now makes colon monitoring widely available and easy to do.

I think these findings will encourage providers to use this system more routinely, and I think it will likely change practice patterns for the good.

Editors’ note: Lacy has relevant disclosures with AbbVie, Ardelyx, Ironwood Pharmaceuticals, Takeda, and others.

Reference

^{Lacy BE, Cangemi DJ, Accurso J, et al. P0232 - Higher Nighttime Colonic Activity Measured by Wireless Patches Linked to Patient Reported Bowel Movement Satisfaction. Paper presented at: ACG 2024 Annual Scientific Meeting. Philadelphia, Pennsylvania. October 25-30, 2024.}