Electrogastrography measurement systems and analysis methods used in clinical practice and research: comprehensive review.

Electrogastrography (EGG) is a non-invasive method with high diagnostic potential for the prevention of gastroenterological pathologies in clinical practice. In this study, a review of the measurement systems, procedures, and methods of analysis used in electrogastrography is presented. A critical review of historical and current literature is conducted, focusing on electrode placement, measurement apparatus, measurement procedures, and time-frequency domain methods of filtration and analysis of the non-invasively measured electrical activity of the stomach. As a result, 129 relevant articles with primary aim on experimental diet were reviewed in this study. Scopus, PubMed, and Web of Science databases were used to search for articles in English language, according to the specific query and using the PRISMA method. The research topic of electrogastrography has been continuously growing in popularity since the first measurement by professor Alvarez 100 years ago, and there are many researchers and companies interested in EGG nowadays. Measurement apparatus and procedures are still being developed in both commercial and research settings. There are plenty variable electrode layouts, ranging from minimal numbers of electrodes for ambulatory measurements to very high numbers of electrodes for spatial measurements. Most authors used in their research anatomically approximated layout with two++ active electrodes in bipolar connection and commercial electrogastrograph with sampling rate of 2 or 4 Hz. Test subjects were usually healthy adults and diet was controlled. However, evaluation methods are being developed at a slower pace, and usually the signals are classified only based on dominant frequency. The main review contributions include the overview of spectrum of measurement systems and procedures for electrogastrography developed by many authors, but a firm medical standard has not yet been defined. Therefore, it is not possible to use this method in clinical practice for objective diagnosis. Systematic Review Registration: https://www.prisma-statement.org/.

Meal effects on gastric bioelectrical activity utilizing body surface gastric mapping in healthy subjects.

BACKGROUND: Gastric sensorimotor disorders are prevalent. While gastric emptying measurements are commonly used, they may not fully capture the underlying pathophysiology. Body surface gastric mapping (BSGM) recently emerged to assess gastric sensorimotor dysfunction. This study assessed varying meal size on BSGM responses to inform test use in a wider variety of contexts. METHODS: Data from multiple healthy cohorts receiving BSGM were pooled, using four different test meals. A standard BSGM protocol was employed: 30-min fasting, 4-h post-prandial, using Gastric Alimetry® (Alimetry, New Zealand). Meals comprised: (i) nutrient drink + oatmeal bar (482 kcal; 'standard meal'); (ii) oatmeal bar alone; egg and toast meal, and pancake (all ~250 kcal). Gastric Alimetry metrics included BMI-adjusted Amplitude, Principal Gastric Frequency, Gastric Alimetry Rhythm Index (GA-RI) and Fed:Fasted Amplitude Ratio (ff-AR). KEY RESULTS: 238 participants (59.2% female) were included. All meals significantly increased amplitude and frequency during the first postprandial hour (p < 0.05). There were no differences in postprandial frequency across meals (p > 0.05). The amplitude and GA-RI of the standard meal (n = 110) were significantly higher than the energy bar alone (n = 45) and egg meal (n = 65) (all p < 0.05). All BSGM metrics were comparable across the three smaller meals (p > 0.05). A higher symptom burden was found in the oatmeal bar group versus the standard meal and pancake meal (p = 0.01, 0.003, respectively). CONCLUSIONS & INFERENCES: The consumption of lower calorie meals elicited different postprandial responses, when compared to the standard Gastric Alimetry meal. These data will guide interpretations of BSGM when applied with lower calorie meals.

Data augmentation for generating synthetic electrogastrogram time series.

To address an emerging need for large number of diverse datasets for rigor evaluation of signal processing techniques, we developed and evaluated a new method for generating synthetic electrogastrogram time series. We used electrogastrography (EGG) data from an open database to set model parameters and statistical tests to evaluate synthesized data. Additionally, we illustrated method customization for generating artificial EGG time series alterations caused by the simulator sickness. Proposed data augmentation method generates synthetic EGG data with specified duration, sampling frequency, recording state (postprandial or fasting state), overall noise and breathing artifact injection, and pauses in the gastric rhythm (arrhythmia occurrence) with statistically significant difference between postprandial and fasting states in > 70% cases while not accounting for individual differences. Features obtained from the synthetic EGG signal resembling simulator sickness occurrence displayed expected trends. The code for generation of synthetic EGG time series is not only freely available and can be further customized to assess signal processing algorithms but also may be used to increase data diversity for training artificial intelligence (AI) algorithms. The proposed approach is customized for EGG data synthesis but can be easily utilized for other biosignals with similar nature such as electroencephalogram.

Antibiotic duration and gastric dysmotility in preterm neonates.

OBJECTIVES: Prolonged antibiotic use after birth is associated with neonatal feeding intolerance and functional gastrointestinal disorders (FGIDs). A gastric dysrhythmia (tachygastria) with frequencies >4-9 cycles per minute, measured by electrogastrography (EGG), is associated with FGIDs. The relationship between prolonged antibiotic use and % time spent in tachygastria is unknown in preterm infants. We aimed to compare weekly changes in % tachygastria between preterm infants receiving long (>48 h) versus short (≤48 h) courses of antibiotics for early onset sepsis evaluation (initiated at <3 days of life). METHODS: This was a longitudinal, prospective cohort study of 88 preterm infants (<34 weeks' gestation) with weekly EGG recordings from the first week of life until 40 weeks' post-menstrual age, discharge, or death. We calculated % of EGG recording time in tachygastria and determined the mean across weekly sessions. A mixed effects model assessed variance in % tachygastria between the short- and long-antibiotic exposure groups across all weeks. RESULTS: Baseline characteristics were similar between the two groups. There was no difference in % tachygastria between short and long antibiotic exposure groups across nine postnatal weeks (p = 0.08). CONCLUSIONS: Early, prolonged antibiotic exposure among preterm infants may not lead to significant gastric dysrhythmia. Future studies including larger sample sizes and a "no antibiotic" exposure arm are essential in elucidating this potential relationship.

Gastric dysrhythmias in patients with early systemic sclerosis: a cross-sectional study.

Objectives: Gastric involvement in patients with early systemic sclerosis (SSc) has not been previously investigated. We aim to evaluate the association of gastric dysrhythmias with gastrointestinal (GI) symptoms and nailfold video capillaroscopy (NVC). Methods: Cross-sectional study. Patients with early SSc, completed the UCLA GIT 2.0 questionnaire, performed an NVC, and a surface Electrogastrography (EGG). Descriptive statistics was used for demographic and clinical characteristics and Fisher and Kendall Tau tests were used for association analysis. Results: 75 patients were screened, 30 patients were consecutively enrolled, 29 performed the EGG and 1 patient had a non-interpretable NVC. 29/30 were female with a mean age of 48.7 years (25-72). The mean disease duration from the first non-RP symptom was 22.6 +/-10.8 months and most of the patients had limited disease (76.6%). Total GIT 2.0 score symptoms were moderate-severe in 63% of the participants and 28/29 had an abnormal EGG. Bradygastria was the most common pattern present in 70% of the participants. NVC patterns: 17% early, 34% active, 28% scleroderma-like, 14% non-specific, and 2 patients had a normal NVC. There was no association between severe GI symptoms or NVC patterns and severely abnormal EGG, but the presence of bradygastria was associated with severe impairment in the social functioning area (p 0.018). Conclusions: Gastric dysmotility is common in early SSc and there is a lack of correlation between GI symptoms and NVC scleroderma patterns. EGG is a sensitive, cheap, and non-invasive exam, that may be an alternative to early diagnosis of GI involvement.

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects.

Functional gastric disorders entail chronic or recurrent symptoms, high prevalence and a significant financial burden. These disorders do not always involve structural abnormalities and since they cannot be diagnosed by routine procedures, electrogastrography (EGG) has been proposed as a diagnostic alternative. However, the method still has not been transferred to clinical practice due to the difficulty of identifying gastric activity because of the low-frequency interference caused by skin-electrode contact potential in obtaining spatiotemporal information by simple procedures. This work attempted to robustly identify the gastric slow wave (SW) main components by applying multivariate variational mode decomposition (MVMD) to the multichannel EGG. Another aim was to obtain the 2D SW vectorgastrogram VGGSW from 4 electrodes perpendicularly arranged in a T-shape and analyse its dynamic trajectory and recurrence quantification (RQA) to assess slow wave vector movement in healthy subjects. The results revealed that MVMD can reliably identify the gastric SW, with detection rates over 91% in fasting postprandial subjects and a frequency instability of less than 5.3%, statistically increasing its amplitude and frequency after ingestion. The VGGSW dynamic trajectory showed a statistically higher predominance of vertical displacement after ingestion. RQA metrics (recurrence ratio, average length, entropy, and trapping time) showed a postprandial statistical increase, suggesting that gastric SW became more intense and coordinated with a less complex VGGSW and higher periodicity. The results support the VGGSW as a simple technique that can provide relevant information on the "global" spatial pattern of gastric slow wave propagation that could help diagnose gastric pathologies.

Characterization of gastric dysfunction after fundoplication using body surface gastric mapping.

BACKGROUND: Adverse gastric symptoms persist in up to 20% of fundoplication operations completed for gastroesophageal reflux disease, causing significant morbidity and driving the need for revisional procedures. Noninvasive techniques to assess the mechanisms of persistent postoperative symptoms are lacking. This study aimed to investigate gastric myoelectrical abnormalities and symptoms in patients after fundoplication using a novel noninvasive body surface gastric mapping (BSGM) device. METHODS: Patients with a previous fundoplication operation and ongoing significant gastroduodenal symptoms and matched controls were included. BSGM using Gastric Alimetry (Alimetry Ltd) was employed, consisting of a high-resolution 64-channel array, validated symptom-logging application, and wearable reader. RESULTS: A total of 16 patients with significant chronic symptoms after fundoplication were recruited, with 16 matched controls. Overall, 6 of 16 patients (37.5%) showed significant spectral abnormalities defined by unstable gastric myoelectrical activity (n = 2), abnormally high gastric frequencies (n = 3), or high gastric amplitudes (n = 1). Patients with spectral abnormalities had higher Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index scores than those of patients without spectral abnormalities (3.2 [range, 2.8-3.6] vs 2.3 [range, 2.2-2.8], respectively; P = .024). Moreover, 7 of 16 patients (43.8%) had BSGM test results suggestive of gut-brain axis contributions and without myoelectrical dysfunction. Increasing Principal Gastric Frequency Deviation and decreasing Rhythm Index scores were associated with symptom severity (r > .40; P < .05). CONCLUSION: A significant number of patients with persistent postfundoplication symptoms displayed abnormal gastric function on BSGM testing, which correlated with symptom severity. Our findings advance the pathophysiologic understanding of postfundoplication disorders, which may inform diagnosis and patient selection for medical therapy and revisional procedures.

Gastric emptying and myoelectrical activity testing in children with esophageal atresia: A pilot study.

Objectives: Abnormalities of gastric function in children with esophageal atresia (EA) could potentially contribute to gastrointestinal symptoms and reduced quality of life (QOL). Therefore, we aimed to determine the feasibility and clinical usefulness of gastric function testing in children with EA. Methods: The validated PedsQL Gastrointestinal Symptoms Questionnaire (PedsQL-GI) was completed to assess gastrointestinal symptoms and symptom-related QOL. Gastric emptying and gastric myoelectrical activity were studied using 13C-gastric emptying octanoic acid breath test (13C-GEBT) and surface electrogastrography (EGG). Correlations between 13C-GEBT and EGG parameters and PedsQL-GI scores were investigated. Results: Fifteen patients (four males) were included (median age: 6 [3.0-8.5] years). Mean PedsQL-GI scores as reported by the children were comparable to the healthy population. However, parents reported a diminished QOL. Gastric function tests (gastric emptying and/or surface EGG) showed abnormalities in 12 patients (80%). Patients with abnormal slow waves showed abnormal gastric emptying coefficient more often. There was no significant association between 13C-GEBT nor EGG results and PedsQL-GI scores. Conclusions: 13C-GEBT and EGG can be used to evaluate gastric function in patients with EA. Abnormal gastric function tests were present in 80% of our cohort. However, abnormal gastric function did not significantly correlate with reported gastrointestinal symptom-related QOL.

Isoflurane anesthesia suppresses gastric myoelectric power in the ferret.

BACKGROUND: Gastric myoelectric signals have been the focus of extensive research; although it is unclear how general anesthesia affects these signals, and studies have often been conducted under general anesthesia. Here, we explore this issue directly by recording gastric myoelectric signals during awake and anesthetized states in the ferret and explore the contribution of behavioral movement to observed changes in signal power. METHODS: Ferrets were surgically implanted with electrodes to record gastric myoelectric activity from the serosal surface of the stomach, and, following recovery, were tested in awake and isoflurane-anesthetized conditions. Video recordings were also analyzed during awake experiments to compare myoelectric activity during behavioral movement and rest. KEY RESULTS: A significant decrease in gastric myoelectric signal power was detected under isoflurane anesthesia compared to the awake condition. Moreover, a detailed analysis of the awake recordings indicates that behavioral movement is associated with increased signal power compared to rest. CONCLUSIONS & INFERENCES: These results suggest that both general anesthesia and behavioral movement can affect the signal power of gastric myoelectric recordings. In summary, caution should be taken in studying myoelectric data collected under anesthesia. Further, behavioral movement could have an important modulatory role on these signals, affecting their interpretation in clinical settings.

Pulsed-field ablation does not induce esophageal and periesophageal injury-A new esophageal safety paradigm in catheter ablation of atrial fibrillation.

INTRODUCTION: Esophageal injury is one of the most serious complications of pulmonary vein isolation (PVI) with thermic energy sources. Better tissue selectivity of primarily non-thermic pulsed field ablation (PFA) may eliminate collateral injury, particularly the risk of atrio-esophageal fistula (AEF). OBJECTIVE: To compare the incidence of any (peri)-esophageal injury following PVI using PFA to thermic energy sources. METHODS: Using endoscopy, endoscopic ultrasound, and electrogastrography before and after PVI, esophageal and periesophageal injury (mucosal lesions, food retention, periesophageal edema, or vagal nerve injury) were assessed following PFA and radiofrequency (RF)- or cryoballoon (CB)-PVI. RESULTS: Between December 2022 and February 2023, 20 patients (67 ± 10 years, 53% male) undergoing PFA (Farapulse, Boston Scientific) for atrial fibrillation (AF) were studied and compared with a previous cohort of 57 patients who underwent thermic PVI (CB: n = 33; RF: n = 24). Following PFA-PVI, none of the patients had mucosal lesions, food retention, or ablation-induced vagal nerve injury; four patients showed periesophageal edema. Following thermic ablation, 33/57 patients (58%) showed esophageal and/or periesophageal injury (CB: 21/33 [64%], RF: 12/24 [50%]), in detail 4/57 mucosal lesions, 18/57 food retention, 17/57 vagal nerve injury, and 20/52 edema. Midterm success rates were similar for all energy sources. CONCLUSION: In contrast to thermic ablation tools, PFA is not associated with relevant esophageal and periesophageal injury, and might, therefore, reduce or eliminate the risk of potentially lethal AEF in interventional treatment of AF. The etiology of ablation-induced periesophageal edema is unknown but has not been shown to be related to lesion progression.

Electrogastrography in patients with gastric motility disorders.

Electrogastrography (EGG) is a novel diagnostic modality for assessing the gastrointestinal tract (GI) that generates spontaneous electrical activity and monitors gastric motility. The aim of this study was to compare patients with functional dyspepsia (FD) and diabetic gastroparesis (D-GP) with healthy controls (CT) to use established findings on abnormalities of gastric motility based on EGG characteristics. In this study, 50 patients with FD, 50 D-GP patients, and 50 CT subjects were studied to compare EGG with discrete wavelet transform models (DWT) to extract signal characteristics using a variety of different qualitative and quantitative metrics from pre-prandial and postprandial states. As a result, higher statistically significant (p < 0.05*) were found in the DWT models based on power spectral density (PSD) analysis in both states. We also present that the correlations between EGG metrics and the presence of FD, D-GP, and CT symptoms were inconsistent. This paper represents that EGG assessments of FD and D-GP patients differ from healthy controls in terms of abnormalities of gastric motility. Additionally, we demonstrate that diverse datasets showed adequate gastric motility responses to a meal. We anticipate that our method will provide a comprehensive understanding of gastric motility disorders for better treatment and monitoring in both clinical and research settings. In conclusion, we present potential future opportunities for precise gastrointestinal electrophysiological disorders.

Reliability and validity of brain-gastric phase synchronization.

Recent studies have reported that various brain regions, mainly sensory, unimodal regions, display phase synchronization with the stomach's slow (0.05 Hz) myoelectrical rhythm. These gastric-brain interactions have broad implications, from feeding behavior to functional gastrointestinal disorders. However, in contrast to other interoceptive signals (e.g., heart rate) and their relation to the brain, little is known about the reliability of these gastric-brain interactions, their robustness to artifacts such as motion, and whether they can be generalized to new samples. Here we examined these aspects in 43 subjects that had undergone multiple runs of concurrent electrogastrography (EGG), brain fMRI, and pulse oximetry. We also repeated all analyses in an open dataset of a highly sampled individual. We found a set of brain regions that were coupled with the EGG signal after controlling for non-grey matter (GM) signals, head motion, and cardiac artifacts. These regions exhibited significant overlap with previous work. However, we also showed that prior to confound regression, the spatial extent of the gastric network was largely overestimated. Finally, we found substantial test-retest reliability in both the brain and the gastric signals when estimated alone, but not for measures of gastric-brain synchrony. Together, these results provide methodological scaffolding for future research into brain-stomach interactions and for a better understanding of the role of the gastric network.

Gastric Myoelectric Activity and Body Composition in Women with Binge Eating Disorder and Bulimia Nervosa: A Preliminary Trial Study.

Women with eating disorders (EDs) often complain of abnormal gastric responses, which may impact their eating patterns and, consequently, their body composition. Binge eating disorder (BED) and bulimia nervosa (BN) have been shown to affect gastric myoelectric activity (GMA), which may provide a basis for the gastric response in this disease population. This study aimed to examine GMA and body composition in patients with an ED compared to age-body mass index (BMI) matched controls. This case-control study included 18 adults diagnosed with BED or BN compared to 19 age-gender-BMI-matched controls. The electrogastrography with water load test was used to measure GMA during fasting and after water loading to satiety. Body composition was measured using a bioelectric impedance analyzer. The results showed that the ED group had a significantly higher water load than the control group and increased percentages of tachygastria times. Comparing the BED and BN subgroups showed differences in body composition status between the subgroups in the form of less fat mass, muscle mass, and total body water in the BN subgroup. In the BN subgroup, fat mass was associated with the average dominant frequency in the EGG. Thus, measuring GMA may be a promising approach to understanding gastric abnormalities in patients with EDs. Therapies targeting improving body composition in women with BED and BN are recommended in future ED management strategies.

Efficacy and safety of the herbal formula Naesohwajung-tang for functional dyspepsia: a randomized, double-blind, placebo-controlled, multi-center trial.

Background: Current treatment and management options for functional dyspepsia (FD) often fail to alleviate symptoms. Naesohwajung-tang (NHT) is a herbal formula frequently used to treat functional dyspepsia in traditional Korean medicine. However, few animal and case reports on the use of Naesohwajung-tang for functional dyspepsia treatment exist, and the clinical evidence remains deficient. Objectives: This study aimed to evaluate the efficacy of Naesohwajung-tang in patients with functional dyspepsia. Methods: We enrolled 116 patients with functional dyspepsia at two study sites in this 4 weeks, randomized, double-blind, placebo-controlled trial and randomly assigned them to either the Naesohwajung-tang or placebo group. To evaluate the efficacy of Naesohwajung-tang, the primary endpoint was a score on the total dyspepsia symptom (TDS) scale after treatment. The overall treatment effect (OTE), single dyspepsia symptom (SDS) scale, food retention questionnaire (FRQ), Damum questionnaire (DQ), functional dyspepsia-related quality of life (FD-QoL) questionnaire, and gastric myoelectrical activity measured using electrogastrography were evaluated as secondary outcomes. Laboratory tests were performed to confirm the safety of the intervention. Results: The 4 weeks administration of Naesohwajung-tang granules demonstrated a significantly higher reduction in the total dyspepsia symptom (p < 0.05) and a higher degree of improvement in the total dyspepsia symptom (p < 0.01) than the placebo group. Patients who underwent Naesohwajung-tang had a significantly higher overall treatment effect and a greater increase in the degree of improvement in scores such as epigastric burning, postprandial fullness, early satiation, functional dyspepsia-related quality of life, and Damum questionnaire (p < 0.05). Additionally, the Naesohwajung-tang group showed a greater effect in preventing a decrease in the percentage of normal gastric slow waves after meals than the placebo group. As a result of subgroup analyses using the degree of improvement in total dyspepsia symptom, Naesohwajung-tang was found to be more effective than placebo in female, younger patients (<65 years), with a high body-mass index (≥22), overlap type, food retention type, and Dampness and heat in the spleen and stomach systems pattern. There was no significant difference in the incidence of adverse events between the two groups. Conclusion: This is the first randomized clinical trial to verify that Naesohwajung-tang leads on symptom relief in patients with functional dyspepsia. Clinical Trial Registration: https://cris.nih.go.kr/cris/search/detailSearch.do/17613, identifier KCT0003405.

Diagnostic Methods for Evaluation of Gastric Motility-A Mini Review.

Gastric motility abnormalities are common in patients with disorders of gut-brain interaction, such as functional dyspepsia and gastroparesis. Accurate assessment of the gastric motility in these common disorders can help understand the underlying pathophysiology and guide effective treatment. A variety of clinically applicable diagnostic methods have been developed to objectively evaluate the presence of gastric dysmotility, including tests of gastric accommodation, antroduodenal motility, gastric emptying, and gastric myoelectrical activity. The aim of this mini review is to summarize the advances in clinically available diagnostic methods for evaluation of gastric motility and describe the advantages and disadvantages of each test.

Pulmonary vein isolation-induced vagal nerve injury and gastric motility disorders detected by electrogastrography: The side effects of pulmonary vein isolation in atrial fibrillation (SEPIA) study.

INTRODUCTION: Safety of pulmonary vein isolation (PVI) has been established in clinical studies. However, despite prevention efforts the incidence of damage to (peri)-esophageal tissue has not decreased, and the pathophysiology is incompletely understood. Damage to vagal nerve branches may be involved in lesion progression to atrio-esophageal fistula. Using electrogastrography, we assessed the incidence of periesophageal vagal nerve injury (VNI) following atrial fibrillation ablation and its association with procedural parameters and endoscopic results. METHODS: Patients were studied using electrogastrography, endoscopy, and endoscopic ultrasound before and after cryoballoon (CB) or radiofrequency (RF) PVI. The incidence of ablation-induced neuropathic pattern (indicating VNI) in pre- and postprocedural electrogastrography was assessed and correlated with endoscopic results and ablation data. RESULTS: Between February 2021 und January 2022, 85 patients (67 ± 10 years, 53% male) were included, 33 were treated with CB and 52 with RF (38 with moderate power moderate duration [25-30 W] and 14 with high power short duration [50 W]). Ablation-induced VNI was detected in 27/85 patients independent of the energy form. Patients with VNI more frequently had postprocedural endoscopically detected pathology (8% mucosal esophageal lesions, 36% periesophageal edema, 33% food retention) but there was incomplete overlap. Pre-existing esophagitis increased the likelihood of VNI. Ablation data and esophageal temperature data did not predict VNI. CONCLUSION: PVI-induced VNI is quite common and independent of ablation energy source. VNI is part of (peri)-esophageal damage and only partially overlaps with endoscopic findings. VNI-associated acidic reflux may be involved in the complex pathophysiology of esophageal lesion progression to fistula.

Impact of exercise duration on gastrointestinal function and symptoms.

The study aimed to determine the impact of exercise duration on gastrointestinal functional responses and gastrointestinal symptoms (GISs) in response to differing exercise durations. Endurance runners (n = 16) completed three trials on separate occasions, randomized to 1 h (1-H), 2 h (2-H), and 3 h (3-H) of running at 60% V̇o2max in temperate ambient temperature. Orocecal transit time (OCTT) was determined by lactulose challenge, with concomitant breath hydrogen (H2) determination. Gastric slow wave activity was recorded using cutaneous electrogastrography (cEGG) before and after exertion. GIS was determined using a modified visual analog scale (mVAS). OCTT response was classified as very slow on all trials (∼93-101 min) with no trial difference observed (P = 0.895). Bradygastria increased postexercise on all trials (means ± SD: 1-H: 10.9 ± 11.7%, 2-H: 6.2 ± 9.8%, and 3-H: 13.2 ± 21.4%; P < 0.05). A reduction in the normal gastric slow wave activity (2-4 cycles/min) was observed postexercise on 1-H only (-10.8 ± 17.6%; P = 0.039). GIS incidence and gut discomfort was higher on 2-H (81% and 12 counts) and 3-H (81% and 18 counts), compared with 1-H (69% and 6 counts) (P = 0.038 and P = 0.006, respectively). Severity of gut discomfort, total-GIS, upper-GIS, and lower-GIS increased during exercise on all trials (P < 0.05). Steady-state exercise in temperate ambient conditions for 1 h, 2 h, and 3 h instigates perturbations in gastric slow wave activity compared with rest and hampers OCTT, potentially explaining the incidence and severity on exercise-associated GIS.NEW & NOTEWORTHY Exercise stress per se appears to instigate perturbations to gastric myoelectrical activity, resulting in an increase in bradygastria frequency, inferring a reduction in gastric motility. The perturbations to gastrointestinal functional responses instigated by exercise per se, likely contribute to the high incidence and severity level of exercise-associated gastrointestinal symptoms. Cutaneous electrogastrography is not commonly used in exercise gastroenterology research, however, may be a useful aid in providing an overall depiction of gastrointestinal function. Particularly relating to gastrointestinal motility and concerning gastroparesis.

Revised spectral metrics for body surface measurements of gastric electrophysiology.

BACKGROUND: Electrogastrography (EGG) non-invasively evaluates gastric function but has not achieved common clinical adoption due to several technical limitations. Body Surface Gastric Mapping (BSGM) has been introduced to overcome these limitations, but pitfalls in traditional metrics used to analyze spectral data remain unaddressed. This study critically evaluates five traditional EGG metrics and introduces improved BSGM spectral metrics, with validation in a large cohort. METHODS: Pitfalls in five EGG metrics were assessed (dominant frequency, percentage time normogastria, amplitude, power ratio, and instability coefficient), leading to four revised BSGM spectral metrics. Traditional and revised metrics were compared to validate performance using a standardized 100-subject database of BSGM tests (30 min baseline; 4-h postprandial) recorded using Gastric Alimetry® (Alimetry). KEY RESULTS: BMI and amplitude were highly correlated (r = -0.57, p < 0.001). We applied a conservative BMI correction to obtain a BMI-adjusted amplitude metric (r = -0.21, p = 0.037). Instability coefficient was highly correlated with both dominant frequency (r = -0.44, p < 0.001), and percent bradygastria (r = 0.85, p < 0.001), in part due to misclassification of low frequency transients as gastric activity. This was corrected by introducing distinct gastric frequency and stability metrics (Principal Gastric Frequency and Gastric Alimetry Rhythm Index (GA-RI)TM ) that were uncorrelated (r = 0.14, p = 0.314). Only 28% of subjects showed a maximal averaged amplitude within the first postprandial hour. Calculating Fed:Fasted Amplitude Ratio over a 4-h postprandial window yielded a median increase of 0.31 (IQR 0-0.64) above the traditional ratio. CONCLUSIONS & INFERENCES: The revised metrics resolve critical pitfalls impairing the performance of traditional EGG, and should be applied in future BSGM spectral analyses.

Gastric myoelectrical activity based AI-derived threshold predicts resolution of gastroparesis post-pyloric balloon dilation.

BACKGROUND: A patient subset with gastroparesis (GP) has normal gastric myoelectrical activity (GMA) and pyloric dysfunction. AIMS: (1) To determine pyloric balloon dilation (BD) effect on symptoms and gastric emptying in GP patients with normal 3 cycles per minute (cpm) GMA. (2) To demonstrate GMA-based artificial intelligence (AI)-derived formulae predict BD success at 10-12-month follow-up. METHODS: Cohort subjects completed baseline electrogastrogram w/water load satiety test (WLST), solid-phase nuclear gastric emptying, Gastrointestinal Cardinal Symptom Index (ANMS GCSI-DD) and Leeds questionnaires. Subjects were divided into two groups based on response to the WLST. Group 1 (n = 26) with hypernormal/normal 3 cpm GMA and Group 2 (n = 4) hyponormal/normal range 3 cpm GMA, compared to healthy normals. All subjects underwent endoscopic pyloric BD. After 10-12 months, gastric emptying and dyspepsia questionnaires were repeated to evaluate outcomes. RESULTS: Group 1 ANMS GCSI-DD scores improved from 2 points at baseline (BL) to 0 at follow-up (f/u) (p < 0.001); Group 2 ANMS GSCI-DD scores were 2 at BL and 1.6 at f/u (p = 0.25). Leeds scores improved (p < 0.001) only for Group 1. Group 1 gastric emptying improved (54.5% retained at 2 h at BL vs. 12.2% at f/u, p < 0.001) in contrast to Group 2 patients (51.25% at BL vs. 56.25% at f/u, p = 0.252). Percentage 3 cpm GMA decreased (41.1% at BL vs. 24.9% at f/u, p ≤ 0.005) in Group 1 versus Group 2 (15.3% at BL vs. 23.4% at f/u, p = 0.114). AI-derived GMA threshold (GMAT) of 0.59 predicted positive pyloric BD outcomes at 10-12 months with sensitivity 96%, specificity 75%, and 93% correct classification. CONCLUSIONS: Pyloric BD improved symptoms and gastric emptying long term in patients with GP and hypernormal/normal 3 cpm GMA. AI-derived GMAT predicted pyloric BD success. GMA post-WLST and GMAT are objective measures for improved selection and outcomes for endoscopic pyloric BD.

Gut-Brain Coupling and Multilevel Physiological Response to Biofeedback Relaxation After a Stressful Task Under Virtual Reality Immersion: A Pilot Study.

Human physiological reactions to the environment are coordinated by the interactions between brain and viscera. In particular, the brain, heart, and gastrointestinal tract coordinate with each other to provide physiological equilibrium by involving the central, autonomic, and enteric nervous systems. Recent studies have demonstrated an electrophysiological coupling between the gastrointestinal tract and the brain (gut-brain axis) under resting-state conditions. As the gut-brain axis plays a key role in individual stress regulation, we aimed to examine modulation of gut-brain coupling through the use of an overwhelming and a relaxing module as a first step toward modeling of the underlying mechanisms. This study was performed in 12 participants who, under a virtual reality environment, performed a 9-min cognitive stressful task followed by a 9-min period of relaxation. Brain activity was captured by electroencephalography, autonomic activities by photoplethysmography, and electrodermal and gastric activities by electrogastrography. Results showed that compared with the stressful task, relaxation induced a significant decrease in both tonic and phasic sympathetic activity, with an increase in brain alpha power and a decrease in delta power. The intensity of gut-brain coupling, as assessed by the modulation index of the phase-amplitude coupling between the normogastric slow waves and the brain alpha waves, decreased under the relaxation relative to the stress condition. These results highlight the modulatory effect of biofeedback relaxation on gut-brain coupling and suggest noninvasive multilevel electrophysiology as a promising way to investigate the mechanisms underlying gut-brain coupling in physiological and pathological situations.