Biomagnetic and bioelectric detection of gastric slow wave activity in normal human subjects—a correlation study

Somarajan, Suseela; Muszynski, Nicole D.; Obioha, Chibuike; Richards, William O.; Bradshaw, Leonard A.

doi:10.1088/0967-3334/33/7/1171

Cited by 10 publications

(9 citation statements)

References 16 publications

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“…Comparison of the mean frequency values of gastric spectral peak did not reveal statistically significant differences among non-obese and their age matched obese counterparts (Riezzo et al , 1991). Since the application of SOBI algorithm improved both MGG and EGG (Somarajan et al , 2012), in the present study, other than EMG, EGG and MGG, we also employed SOBI-EGG and SOBI-MGG for dominant frequency calculation. Our data showed that increases in BMI do not have any influence on dominant frequencies determined using these modalities.…”

Section: Discussionmentioning

confidence: 99%

Effects of body mass index on gastric slow wave: a magnetogastrographic study

et al. 2014

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We measured gastric slow wave activity simultaneously with magnetogastrogram (MGG), mucosal electromyogram (EMG) and electrogastrogram (EGG) in human subjects with varying body mass index (BMI) before and after a meal. In order to investigate the effect of BMI on gastric slow wave parameters, each subject’s BMI was calculated and divided into two groups: subjects with BMI ≤ 27 and BMI > 27. Signals were processed with Fourier spectral analysis and Second-Order Blind Identification (SOBI) techniques. Our results showed that increased BMI does not affect signal characteristics such as frequency and amplitude of EMG and MGG. Comparison of the postprandial EGG power, on the other hand, showed a statistically significant reduction in subjects with BMI > 27 compared with BMI ≤ 27. In addition to the frequency and amplitude, the use of SOBI-computed propagation maps from MGG data allowed us to visualize the propagating slow wave and compute the propagation velocity in both BMI groups. No significant change in velocity with increasing BMI or meal was observed in our study. In conclusion, multichannel MGG provides assessment of frequency, amplitude and propagation velocity of the slow wave in subjects with differing BMI categories and were observed to be independent of BMI.

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Section: Discussionmentioning

confidence: 99%

Effects of body mass index on gastric slow wave: a magnetogastrographic study

et al. 2014

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“…Second order blind identification decomposes the multichannel SQUID data into separate signal and noise components. Gastric signal components were identified by a blinded observer as primarily sinusoidal signals with dominant peaks in FFT frequency spectra in a range of frequencies between 1 and 9 cpm . We reconstructed MGG from SOBI components (SOBI‐MGG) by isolating gastric components and projecting them spatially to the sensor array.…”

Section: Methodsmentioning

confidence: 99%

“…Slow waves also produce extracellular magnetic fields which may be measured in the magnetogastrogram (MGG) with Superconducting Quantum Interference Device (SQUID) magnetometers . Magnetic fields are relatively insensitive to the effect of abdominal tissue layers .…”

Section: Introductionmentioning

confidence: 99%

“…16 Slow waves also produce extracellular magnetic fields which may be measured in the magnetogastrogram (MGG) with Superconducting Quantum Interference Device (SQUID) magnetometers. 17 Magnetic fields are relatively insensitive to the effect of abdominal tissue layers. 9 In addition to temporal dynamics of the slow wave, MGG preserves phase characteristics of slow wave signals from spatially separated gastric sources allowing the characterization of propagation.…”

Section: Introductionmentioning

confidence: 99%

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Diabetic gastroparesis alters the biomagnetic signature of the gastric slow wave

Bradshaw

Cheng

Chung

et al. 2016

Neurogastroenterology Motil

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Background Gastroparesis is characterized by delayed gastric emptying without mechanical obstruction, but remains difficult to diagnose and distinguish from other GI disorders. Gastroparesis affects the gastric slow wave, but noninvasive assessment has been limited to the electrogastrogram (EGG), which reliably characterizes temporal dynamics but does not provide spatial information. Methods We measured gastric slow wave parameters from the EGG and magnetogastrogram (MGG) in patients with gastroparesis and in healthy controls. In addition to dominant frequency (DF) and percentage power distribution (PPD), we measured the propagation velocity from MGG spatiotemporal patterns and the percentage of slow wave coupling (%SWC) from EGG. Key Results No significant difference in DF was found between patients and controls. Gastroparesis patients had lower percentages of normogastric frequencies (60 ± 6% vs 78 ± 4%, p<0.05), and higher brady- (9 ± 2% vs 2 ± 1%, p<0.05) and tachygastric (31 ± 2 % vs 19 ± 1%, p<0.05) frequency content postprandial, indicative of uncoupling. Propagation patterns were substantially different in patients and longitudinal propagation velocity was retrograde at 4.3 ± 2.9 mm/s vs anterograde at 7.4 ± 1.0 mm/s for controls (p < 0.01). No difference was found in %SWC from EGG. Conclusions & Inferences Gastric slow wave parameters obtained from MGG recordings distinguish gastroparesis patients from controls. Assessment of slow wave propagation may prove critical to characterization of underlying disease processes. Future studies should determine pathologic indicators from MGG associated with other functional gastric disorders, and whether multichannel EGG with appropriate signal processing also reveals pathology.

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“…The theoretical formulation proposed here is based on a continuum thermodynamical framework for smooth muscle cell contraction (44,63) and was applied to HCMS modeling. Such an approach has received growing attention due to its general statements and applicability in a wide range of smooth muscle tissue models (61,64).…”

Section: Methodsmentioning

confidence: 99%

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

Altomare

Gizzi

Guarino

et al. 2014

American Journal of Physiology-Gastrointestinal and Liver Physi

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It has been shown, in animal models, that gastrointestinal tract (GIT) motility is influenced by temperature; nevertheless, the basic mechanism governing thermal GIT smooth muscle responses has not been fully investigated. Studies based on physiologically tuned mathematical models have predicted that thermal inhomogeneity may induce an electrochemical destabilization of peristaltic activity. In the present study, the effect of thermal cooling on human colonic muscle strip (HCMS) contractility was studied. HCMSs were obtained from disease-free margins of resected segments for cancer. After removal of the mucosa and serosa layers, strips were mounted in separate chambers. After 30 min, spontaneous contractions developed, which were measured using force displacement transducers. Temperature was changed every hour (37, 34, and 31°C). The effect of cooling was analyzed on mean contractile activity, oscillation amplitude, frequency, and contraction to ACh (10(-5) M). At 37°C, HCMSs developed a stable phasic contraction (~0.02 Hz) with a significant ACh-elicited mean contractile response (31% and 22% compared with baseline in the circular and longitudinal axis, respectively). At a lower bath temperature, higher mean contractile amplitude was observed, and it increased in the presence of ACh (78% and 43% higher than the basal tone in the circular and longitudinal axis, respectively, at 31°C). A simplified thermochemomechanical model was tuned on experimental data characterizing the stress state coupling the intracellular Ca(2+) concentration to tissue temperature. In conclusion, acute thermal cooling affects colonic muscular function. Further studies are needed to establish the exact mechanisms involved to better understand clinical consequences of hypothermia on intestinal contractile activity.

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Biomagnetic and bioelectric detection of gastric slow wave activity in normal human subjects—a correlation study

Cited by 10 publications

References 16 publications

Effects of body mass index on gastric slow wave: a magnetogastrographic study

Effects of body mass index on gastric slow wave: a magnetogastrographic study

Diabetic gastroparesis alters the biomagnetic signature of the gastric slow wave

Experimental evidence and mathematical modeling of thermal effects on human colonic smooth muscle contractility

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