Concordance between colonic myoelectrical signals recorded with intramuscular electrodes in the human rectosigmoid in vivo

Pilot Validation of a New Wireless Patch System as an Ambulatory, Noninvasive Tool That Measures Gut Myoelectrical Signals: Physiologic and Disease Correlations

BACKGROUND AND AIMS

Limited means exist to assess gastrointestinal activity in a noninvasive, objective way that is highly predictive of underlying motility disorders. The aim of this paper is to demonstrate the feasibility of recording myoelectric gastrointestinal activity by cutaneous patches and to correlate myoelectric signals with gastrointestinal function in various clinical settings.

METHODS

A novel wireless patch system (WPS) (G-Tech Medical) that acquires gastrointestinal myoelectrical signals was placed on the patients' anterior abdomens. Data were transmitted wirelessly to a mobile device with a user interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters, and nominally assigned them to specific gastrointestinal organs based on their frequencies.

RESULTS

The inherent reproducibility of the WPS measurement technique itself and from the underlying gut activity, coupled with source validation and sensitivity to changes in gut activity in several physiologic and pathologic states, demonstrates its feasibility, safety, and performance in clinical settings.

CONCLUSIONS

The novel WPS technology, measuring myoelectric intestinal activity noninvasively and continuously over multiple days, is feasible in a wide range of clinical settings, highlighting its promise in the diagnosis and management of motility disorders. Further research is required for more extensive validation and to determine how best to employ this information to optimize patient care.

Smooth muscle electromyography from rat urethra

Electrical signals recorded from the penis have been suggested as reflecting electromyographic activity in the underlying smooth muscles. In order to verify this assertion, we manipulated the signal recorded from rat urethra surface. Stimulation of the pelvic nerve brought about a reduction of activity (965 +/- 826 to 166 +/- 143 microV, root mean square of the power at range 0.005-1 Hz, P = 0.008), with a significant frequency-response relationship (P = 0.0002). This effect was not altered by temporary closure of the aorta (P = 0.89), thus ruling out hemodynamic artifact as a possible cause of signal change during stimulation. Our findings support the assertion that the signal indeed reflects activity in smooth muscle.

Intermittent bursts of motor activity in the human rectum and absence of propagation

Manometric recordings from multiple sites were performed to determine the propagating properties of intermittent bursts of motor activity in the human rectum. Pressure changes were recorded simultaneously at 12.5 cm, 10 cm and 7.5 cm from the anal verge in nine healthy subjects for a total recording time of 32 hours, each study lasting 2.7-4.8 hours. The burst motor activity was identified on 19 occasions in 7 of 9 subjects at 12.5 cm; 26 occasions in all subjects at 10 cm; and 11 occasions in 3 of 9 subjects at 7.5 cm. In most cases, the burst motor activity was observed at a single recording site while other recording sites were quiescent. It did not appear to migrate in either an oral or aboral direction. The burst motor activity contained in part runs of pressure waves with a regular frequency: at 12.5 and 10 cm of the recording site, runs of regular pressure waves were dominated by a frequency of 2.5-5 cycle per minute, whereas those at 7.5 cm occurred with a higher frequency and a lower amplitude as compared with the more proximal recording sites. No evidence of propagation of each pressure wave was seen even when the burst occurred simultaneously at more than two recording sites. These results suggest that the intermittent bursts of rectal motor activity occur locally and do not propagate in either on oral or aboral direction. They appear dissimilar to the interdigestive migrating motor complex observed in the more proximal part of the gut.