Effect of Body Mass Index on the sensitivity of Magnetogastrogram and Electrogastrogram

Area of Science:

• Gastroenterology
• Biomedical Engineering
• Medical Physics

Background:

• Gastric slow wave activity is crucial for gastric motility and function.
• Cutaneous electrogastrogram (EGG) measures gastric electrical activity but is influenced by abdominal wall conductivity.
• Magnetogastrogram (MGG) measures gastric magnetic fields, potentially overcoming EGG's limitations.

Purpose of the Study:

• To compare the sensitivity of MGG and EGG to body mass index (BMI) and waist circumference.
• To investigate whether MGG is less affected by obesity than EGG.

Main Methods:

• Simultaneous recording of gastric slow wave signals using mucosal electrodes, a Superconducting Quantum Interference Device (SQUID) magnetometer for MGG, and cutaneous electrodes for EGG.
• Data collected before and after a test meal from human volunteers.
• Comparison of EGG and MGG sensitivity against volunteer BMI and waist circumference.

Main Results:

• A significant reduction in post-prandial EGG sensitivity was observed in subjects with BMI ≥ 25.
• A similar reduction in post-prandial MGG sensitivity was only seen in subjects with BMI ≥ 30.
• The sensitivity of both EGG and MGG, when analyzed using Second Order Blind Identification (SOBI), was unaffected by anthropometric measurements.

Conclusions:

• Magnetogastrogram (MGG) demonstrates superior robustness to variations in body mass index and waist circumference compared to electrogastrogram (EGG).
• The application of Second Order Blind Identification (SOBI) enhances the sensitivity and stability of both EGG and MGG recordings, rendering them independent of anthropometric factors.