P057 WIRELESS ELECTRODE PATCHES SHOW INTRAPATIENT REPRODUCIBILITY IN A LONGITUDINAL STUDY OF PATIENTS WITH CROHN'S DISEASE IN REMISSION

Abstract Background Crohn’s disease (CD) patients would benefit from a non-invasive indicator of gut function to better predict changes in disease state, such as the onset of flare. A study of CD patients using non-invasive wireless electrode patches (G-Tech Medical, Mountain View, CA) that read myoelectric signals from the gut over 3 days is underway at Stanford University’s IBD center. The study will include 40 patients presenting in flare and 30 in remission to be tested at t=0, 1, 3 and 6 months. In addition, one-time tests will be performed on 20 healthy controls. Aims Herein, we report on the first 6 CD patients tested at t=0 and 1 month while in remission. Methods Each patient wore 3 abdominal patches (each 2.7” diameter) for 3 consecutive days while pursuing regular daily activities and meals (Figure 1). Each patch recorded 4 channels of myoelectric activity from the stomach, small intestine and colon, and transmitted the raw data to an iPod Touch, which relayed the data to a secure cloud server. Data were later downloaded and processed to remove artifacts, create frequency spectra, and search them for peaks representing rhythmic motor activity. We find that, nominally, stomach activity appears at 3 cycles/minute (cpm), small intestine at 6–12 cpm, and colon at 12–25 cpm. Results Figure 2 shows peak spectra for the 6 patients at t=0 and 1 month. Individual peaks represent motor activity at a specific frequency associated with the stomach, small intestine, or colon. Each patient has a unique overall pattern, or GutPrint, reflecting the frequencies and levels of activity of their GI motility. The GutPrint for each individual reproduces well at the second test and is easily recognizable for each subject. Although the peak amplitudes may vary, virtually all of the peaks that appear at specific frequencies at t=0 are also present at 1 month representing a quantifiable signature that reflects each patient’s unique motility. Conclusion The G-Tech patch system provides a practical and noninvasive, physiologic means of measuring motor activity of the gut over multiple days. Its intra-patient reproducibility allows for the possibility of measuring changes to gut performance over time, whether naturally- or drug-induced, showing promise in CD monitoring.