A novel scalable electrode array and system for non-invasively assessing gastric function using flexible electronics.

BACKGROUND: Disorders of gastric function are highly prevalent, but diagnosis often remains symptom-based and inconclusive. Body surface gastric mapping is an emerging diagnostic solution, but current approaches lack scalability and are cumbersome and clinically impractical. We present a novel scalable system for non-invasively mapping gastric electrophysiology in high-resolution (HR) at the body surface. METHODS: The system comprises a custom-designed stretchable high-resolution "peel-and-stick" sensor array (8 × 8 pre-gelled Ag/AgCl electrodes at 2 cm spacing; area 225 cm2 ), wearable data logger with custom electronics incorporating bioamplifier chips, accelerometer and Bluetooth synchronized in real-time to an App with cloud connectivity. Automated algorithms filter and extract HR biomarkers including propagation (phase) mapping. The system was tested in a cohort of 24 healthy subjects to define reliability and characterize features of normal gastric activity (30 m fasting, standardized meal, and 4 h postprandial). KEY RESULTS: Gastric mapping was successfully achieved non-invasively in all cases (16 male; 8 female; aged 20-73 years; BMI 24.2 ± 3.5). In all subjects, gastric electrophysiology and meal responses were successfully captured and quantified non-invasively (mean frequency 2.9 ± 0.3 cycles per minute; peak amplitude at mean 60 m postprandially with return to baseline in <4 h). Spatiotemporal mapping showed regular and consistent wave activity of mean direction 182.7° ± 73 (74.7% antegrade, 7.8% retrograde, 17.5% indeterminate). CONCLUSIONS AND INFERENCES: BSGM is a new diagnostic tool for assessing gastric function that is scalable and ready for clinical applications, offering several biomarkers that are improved or new to gastroenterology practice.

Abnormalities on Electrogastrography in Nausea and Vomiting Syndromes: A Systematic Review, Meta-Analysis, and Comparison to Other Gastric Disorders.

BACKGROUND: Functional nausea and vomiting syndromes and gastroparesis, collectively grouped as nausea and vomiting syndromes (NVS), are overlapping conditions with incompletely understood pathophysiology. Gastric slow wave abnormalities are thought to contribute. AIMS: This study aimed to systematically review and meta-analyze the prevalence of slow wave abnormalities measured by electrogastrography (EGG) in patients with NVS. METHODS: MEDLINE, EMBASE, EMBASE classic, and CENTRAL databases were systematically searched for articles using EGG in adults (≥ 18 years) with NVS. EGG metrics of interest were percentage time in bradygastria, normogastria, and tachygastria as well as dominant frequency and dominant power. Outcomes were also compared with functional dyspepsia (FD), gastroesophageal reflux disease (GORD), and control cohorts. RESULTS: Seven hundred and sixty NVS patients and 308 controls were included from 24 studies. Overall, 64% of patients had EGG abnormalities. Average percent time in normogastria was low during fasting (50%; 95% CI 40-63%) and fed (53%; 95% CI 41-68%) states in patients, with substantial periods in fasting bradygastria (34.1%; 95% CI 25-47%) and postprandial tachygastria (21%; 95% CI 17-26%). Across gastric disorders, pooling of 84 studies showed a comparably high prevalence of EGG abnormalities in NVS (24 studies; n = 760) and GORD (13 studies; n = 427), compared to FD (47 studies; n = 1751) and controls (45 studies; n = 1027). CONCLUSIONS: Frequency-based gastric slow wave abnormalities are prominent in NVS. The strength and consistency of these associations across many studies suggests that gastric dysrhythmia may be an important factor in NVS, motivating the development of more reliable methods for their clinical assessment.

Electrogastrography Abnormalities in Pediatric Gastroduodenal Disorders: A Systematic Review and Meta-analysis.

ABSTRACT: Electrogastrography (EGG) is a non-invasive method of measuring gastric electrophysiology. Abnormal gastric electrophysiology is thought to contribute to disease pathophysiology in patients with gastroduodenal symptoms but this has not been comprehensively quantified in pediatric populations. This study aimed to quantify the abnormalities in gastric electrophysiology on EGG in neonatal and pediatric patients.Databases were systematically searched for articles utilizing EGG in neonatal and pediatric patients (≤18 years). Primary outcomes were prevalence of abnormality, percentage of time in normal rhythm, and power ratio. Secondary outcomes were correlations between patient symptoms and abnormal gastric electrophysiology on EGG.A total of 33 articles (1444 participants) were included. EGG methodologies were variable. Pooled prevalence of abnormalities on EGG ranged from 61% to 86% in patients with functional dyspepsia (FD), gastro-esophageal reflux disease (GERD), and type 1 diabetes mellitus (T1DM). FD patients averaged 20.8% (P = 0.011) less preprandial and 21.6% (P = 0.031) less postprandial time in normogastria compared with controls. Electrophysiological abnormalities were inconsistent in GERD. T1DM patients averaged 46.2% (P = 0.0003) less preprandial and similar (P = 0.32) postprandial time in normogastria compared with controls, and had a lower power ratio (SMD -2.20, 95% confidence interval [CI]: -4.25 to -0.15; P = 0.036). Symptom correlations with gastric electrophysiology were inconsistently reported.Abnormalities in gastric electrophysiology were identifiable across a range of pediatric patients with gastroduodenal symptoms on meta-analysis. However, techniques have been inconsistent, and standardized and more reliable EGG methods are desirable to further define these findings and their potential utility in clinical practice.

Clinical associations of functional dyspepsia with gastric dysrhythmia on electrogastrography: A comprehensive systematic review and meta-analysis.

BACKGROUND: Functional dyspepsia (FD) is a common gastroduodenal disorder, yet its pathophysiology remains poorly understood. Bioelectrical gastric slow-wave abnormalities are thought to contribute to its multifactorial pathophysiology. Electrogastrography (EGG) has been used to record gastric electrical activity; however, the clinical associations require further evaluation. AIMS: This study aimed to systematically assess the clinical associations of EGG in FD. METHODS: MEDLINE, EMBASE, and CENTRAL databases were systematically searched for articles using EGG in adults with FD. Primary outcomes were percentage normal versus abnormal rhythm (bradygastria, normogastria, and tachygastria). Secondary outcomes were dominant power, dominant frequency, percentage coupling, and the meal responses. RESULTS: 1751 FD patients and 555 controls from 47 studies were included. FD patients spent less time in normogastria while fasted (SMD -0.74; 95%CI -1.22 to -0.25) and postprandially (-0.86; 95%CI -1.35 to -0.37) compared with controls. FD patients also spent more fasted time in bradygastria (0.63; 95%CI 0.33-0.93) and tachygastria (0.45; 95%CI 0.12-0.78%). The power ratio (-0.17; 95%CI -0.83-0.48) and dominant frequency meal-response ratio (0.06; 95%CI -0.08-0.21) were not significantly different to controls. Correlations between EGG metrics and the presence and timing of FD symptoms were inconsistent. EGG methodologies were diverse and variably applied. CONCLUSION: Abnormal gastric slow-wave rhythms are a consistent abnormality present in FD, as defined by EGG and, therefore, likely play a role in pathophysiology. The aberrant electrophysiology identified in FD warrants further investigation, including into underlying mechanisms, associated spatial patterns, and symptom correlations.

Gastric dysrhythmia in gastroesophageal reflux disease: a systematic review and meta-analysis.

BACKGROUND: Gastroesophageal reflux disease (GERD) is a commonly diagnosed gastrointestinal disorder, with a substantial impact on the quality of life. The underlying pathophysiology of GERD is multifactorial and incompletely understood. Abnormal gastric electrical activity, measured using electrogastrography (EGG), may contribute. This study aimed to systematically review and meta-analyse the existing literature in which EGG was used in patients with GERD. METHODS: Databases were systematically searched for studies using EGG in adults with GERD. The primary outcome was the percentage of recording time in the normogastric frequency range. Secondary outcomes were dominant frequency, dominant power, power ratio and prevalence of any EGG abnormality. RESULTS: In total, 591 participants (427 patients with GERD; 164 healthy controls) from 13 studies were included. GERD patients spent 17.3% (SMD - 1.18, 95%CI: - 1.84, - 0.52) and 18.7% (SMD - 1.11, 95%CI: - 1.55, - 0.68) less of the preprandial and postprandial recording time in normogastric frequency ranges, respectively, compared to healthy controls. The dominant frequency, dominant power and power ratio were not significantly different to healthy controls in the preprandial and postprandial periods. The pooled prevalence of any EGG abnormality was significantly greater in patients with GERD than in healthy controls [46% (95%CI: 39-64%) vs. 10% (95%CI: 4-23%); p < 0.0001]. Correlations between GERD symptoms and EGG recordings were inconsistently studied. EGG techniques were heterogeneous. CONCLUSIONS: Consistent abnormalities in gastric slow-wave activity, as measured by EGG, were identified in adults with GERD. Further investigation into these abnormalities using novel emerging electrophysiology techniques is desirable, to better define their contribution toward GERD pathophysiology.