Detection of Monophasic Slow-wave Activation Phase Using Wavelet Decomposition

Quantification of Gastric Slow Wave Velocity using Bipolar High-Resolution Recordings

OBJECTIVE

Gastric bio-electrical slow waves are, in part, responsible for coordinating motility. High-resolution (HR) in vivo recordings can be used to capture the wavefront velocity of the propagating slow waves. A standard marking-and-grouping approach is typically employed along with manual review. Here, a bipolar velocity estimation (BVE) method was developed, which utilized local directional information to estimate the wavefront velocity in an efficient manner.

METHODS

With this approach, unipolar in vivo HR recordings were used to construct bipolar recordings in different directions. Then, the local directionality of the slow wave was extracted by calculating time delay information. The accuracy of the method was verified using synthetic data and then validated with in vivo HR pig experimental recordings.

RESULTS

Against ventilator noise amplitude of 0% - 70% of the average slow wave amplitude, the direction and speed error increased from 4.4 and 0.9 mm/s to 8.6 and 1.4 mm/s. For signals added with high-frequency noise with signal-to-noise ratios of 60 dB - 12 dB, the error increased from 8.0 and 1.0 mm/s to 9.8 and 1.2 mm/s. For experimental signals, the BVE algorithm resulted in 19.2 1.7 of direction error and 2.0 0.2 mm/s of speed error, when compared to the standard marking-and-grouping method.

CONCLUSION

Gastric slow wave wavefront velocities were estimated rapidly using the BVE algorithm with minimal errors.

SIGNIFICANCE

The BVE algorithm enables the ability to estimate wavefront velocities in HR recordings in an efficient manner.