Neurogastroenterology & Motility

BackgroundChronic gastroduodenal symptoms arise from heterogenous gastric motor dysfunctions. This study applied multimodal physiological testing using gastric emptying scintigraphy (GES) with intragastric meal distribution (IMD) and Gastric Alimetry(R) body surface gastric mapping (BSGM) to define motility and symptom associations. MethodsPatients with chronic gastroduodenal symptoms underwent simultaneous supine GES and BSGM with 30 m baseline, 99mTC-labelled egg meal, and 4 h postprandial recording. IMD (ratio of counts in the proximal half of the stomach to the total gastric counts) was calculated immediately after the meal (IMD0), with <0.568 defining impaired accommodation. BSGM phenotyping followed a consensus approach, based on normative spectral reference intervals. ResultsAmong 67 patients (84% female, median age 40, median BMI 24), median IMD0 was 0.76 (IQR 0.69-0.86) with 5 (7.5%) meeting impaired accommodation criteria. Delayed gastric emptying (n=18) was associated with higher IMD0 (median 0.9 vs 0.7, p=0.004). On BSGM, 15 patients had abnormal spectrograms (5 [7.5%] high frequency and 10 (14.9%) low rhythm stability and/or amplitude); and in these patients, higher IMD0 (proximal retention) strongly correlated to delayed BSGM meal responses (R=-0.71, p=0.003). Lower IMD, indicating antral distribution, correlated with higher gastric frequencies (R=-0.27, p=0.03). BSGM abnormalities paired with impaired accommodation were associated with worse dyspeptic symptoms. ConclusionProximal retention of food as assessed by intragastric meal distribution correlated with delayed emptying, and in the presence of neuromuscular spectral abnormalities (abnormal frequencies or rhythms), delayed motility responses on BSGM. Patients with multiple motor abnormalities experience worse dyspeptic symptoms.

ObjectivesGastric emptying testing (GET) assesses gastric motility, however is non-specific and insensitive for neuromuscular disorders. Gastric Alimetry(R) (GA) is a new medical device combining non-invasive gastric electrophysiological mapping and validated symptom profiling. This study assessed patient-specific phenotyping using GA compared to GET. MethodsPatients with chronic gastroduodenal symptoms underwent simultaneous GET and GA, comprising a 30-minute baseline, 99mTC-labelled egg meal, and 4-hour postprandial recording. Results were referenced to normative ranges. Symptoms were profiled in the validated GA App and phenotyped using rule-based criteria based on their relationships to the meal and gastric activity: i) sensorimotor; ii) continuous; and iii) other. Results75 patients were assessed; 77% female. Motility abnormality detection rates were: GET 22.7% (14 delayed, 3 rapid); GA spectral analysis 33.3% (14 low rhythm stability / low amplitude; 5 high amplitude; 6 abnormal frequency); combined yield 42.7%. In patients with normal spectral analysis, GA symptom phenotypes included: sensorimotor 17% (where symptoms strongly paired with gastric amplitude; median r=0.61); continuous 30%; other 53%. GA phenotypes showed superior correlations with GCSI, PAGI-SYM, and anxiety scales, whereas Rome IV Criteria did not correlate with psychometric scores (p>0.05). Delayed emptying was not predictive of specific GA phenotypes. ConclusionsGA improves patient phenotyping in chronic gastroduodenal disorders in the presence and absence of motility abnormalities with improved correlation with symptoms and psychometrics compared to gastric emptying status and Rome IV criteria. These findings have implications for the diagnostic profiling and personalized management of gastroduodenal disorders. Study Highlights1) WHAT IS KNOWN O_LIChronic gastroduodenal symptoms are common, costly and greatly impact on quality of life C_LIO_LIThere is a poor correlation between gastric emptying testing (GET) and symptoms C_LIO_LIGastric Alimetry(R) is a new medical device combining non-invasive gastric electrophysiological mapping and validated symptom profiling C_LI 2) WHAT IS NEW HERE O_LIGastric Alimetry generates a 1.5x higher yield for motility abnormalities than GET C_LIO_LIWith symptom profiling, Gastric Alimetry identified 2.7x more specific patient categories than GET C_LIO_LIGastric Alimetry improves clinical phenotyping, with improved correlation with symptoms and psychometrics compared to GET C_LI

BackgroundVomiting is a symptom of various gastrointestinal (GI) disorders and may invalidate gastric emptying tests. Body surface gastric mapping (BSGM) is a clinical test to assess motor vs. sensory contributors to GI symptoms. AimsWhile previous studies have observed myoelectrical dysrhythmias associated with vomiting, the effects of vomiting on BSGM testing have not been defined. MethodsA large clinical database of de-identified BSGM tests was queried for vomiting events, noted by symptom markers via an integrated symptom reporting App. Tests with pre-meal or >2 vomiting events were excluded. Spectrograms and clinical reports were qualitatively assessed. Key BSGM metrics, including the Gastric Alimetry Rhythm Index (GA-RI) and BMI-adjusted amplitude, were interrogated in 5 min epochs for quantitative analysis. ResultsA total of 49 vomit events were included. Vomiting typically had little effect, though was sometimes characterised by small, temporary decreases in BMI-adjusted amplitude or GA-RI. Prolonged periods (> 10 mins) of low amplitude were observed in 4 cases (8%). A mixed effects model revealed a transient decrease in GA-RI in the 5 mins before ({Delta} = -0.27; p < 0.001) and after vomiting ({Delta} = -0.21; p = 0.014), but not in subsequent periods (all p > 0.05). Other metrics were unaffected. Nausea, bloating, and excessive fullness symptoms decreased following vomiting (all p < 0.05). ConclusionsTransient amplitude and rhythm decreases were observed concurrent to vomiting, but subsequently normalised. While additional considerations may be required during test interpretation, the overall impact of vomiting on BSGM test interpretation is minimal.

BackgroundChronic gastroduodenal symptoms are challenging to diagnose and treat. Body surface gastric mapping provides non-invasive biomarkers of gastric function, but the requirement of a standard meal for postprandial assessment can be difficult for severely symptomatic patients. AimsTo assess the impact of reduced meal sizes and fasting on body surface gastric mapping metrics to determine clinical interpretability under non-standard nutritional loads. MethodsHealthy controls (n=60) underwent a 4.5-hour Gastric Alimetry test. Three age, sex, and BMI-matched groups (n=20 each) were compared: Standard Meal (482 kCal), Nutrient bar + Water (250 kcal), and Fasted (no meal). Principal Gastric Frequency, Gastric Alimetry Rhythm Index, BMI-Adjusted Amplitude, and fed:fasted Amplitude Ratio were analyzed against normative intervals. ResultsMeal status significantly affected amplitude-based metrics; the Standard Meal group exhibited higher BMI-Adjusted Amplitude (p<0.001) and fed:fasted Amplitude Ratio (p=0.001) than Fasted and Bar + Water groups. Frequency and rhythm-based metrics were resilient; Principal Gastric Frequency (p=0.245) and Gastric Alimetry Rhythm Index (p=0.336) showed no significant differences across conditions. While amplitude deviations were common in the Fasted group (20% fell below the normative range), Gastric Alimetry Rhythm Index and Principal Gastric Frequency remained within normal reference ranges for 95% of participants across all conditions. ConclusionsWhile consuming <50% of the standard meal significantly reduces gastric amplitude, gastric rhythm remains stable. Principal Gastric Frequency and Gastric Alimetry Rhythm Index function as reliable biomarkers of gastric myoelectrical function regardless of nutritional state.

ObjectiveBody surface gastric mapping (BSGM) non-invasively assesses gastric myoelectrical activity along with real-time symptom reporting. In adults, the development of normative intervals has underpinned new explanatory phenotypes, aiding clinical decision-making. This study established normative reference intervals for adolescent BSGM metrics. Study DesignHealthy adolescents aged 12-17 years with a BMI <35 kg/m2 were recruited from New Zealand, Australia and the United States. BSGM using Gastric Alimetry (Alimetry, New Zealand) involved a 30-minute fast, followed by a 480-kcal meal, and a 4-hour postprandial recording. Reference intervals were calculated for four validated metrics: Principal Gastric Frequency (PGF), body mass index (BMI)-adjusted amplitude, Gastric Alimetry Rhythm Index (GA-RI, indicating rhythm stability), and the fed-to-fasted amplitude ratio (ff-AR). Results were reported at the median and 5th and/or 95th percentiles as appropriate. ResultsA total of 107 participants (52.8% female, median age 14 [IQR 13-16], median BMI 20.1 [IQR 18.75-22.40]) with mixed ethnicities were included. No substantive correlations were observed between BSGM metrics and demographics or anthropometric data. Therefore, a single set of normative reference intervals was established. Median PGF was 3.06 cycles per minute; reference interval 2.72-3.37. Median BMI-adjusted amplitude was 37.80 {micro}V; reference interval 20.0-72.0. Median GA-RI was 0.51; reference interval [&ge;]0.22. Median ff-AR was 2.12; reference interval [&ge;]1.0. ConclusionThis study presents normative reference intervals for BSGM spectral metrics in adolescent populations, informing the interpretation of tests in research and clinical practice.

BackgroundCurrent approaches to symptom-based classifications in gastroduodenal disorders are binary and substantially overlapping. We aimed to develop a standardized and quantitative system for classifying patient-level symptom profiles guided on physiological principles. MethodsA large database (n = 787) of 4.5 h (30 min baseline; 4-h postprandial) Gastric Alimetry (Alimetry, NZ) recordings were used to identify, and quantify distinct symptom patterns based on established gastroduodenal physiology concepts. Tests comprised a standardized meal challenge and symptoms were simultaneously recorded at minimum 15 minute intervals using a 10-point likert scale with pictograms encoded in a validated digital App. Key ResultsSix symptom profiles were defined. The meal change metric was used to define meal-induced and meal-relieved symptom profiles, defined as an increase (+2) or decrease (-2) in the average symptom severity between the first post- and pre-prandial hours of recordings. The continuous profile was defined as a reduced range (<3; i.e., difference between the 95th and 5th percentile symptom severity), and thresholded to the 5th percentile of symptom severity being > 2. The symptom/amplitude correlation metric defined the sensorimotor profile, thresholded when the correlation was >0.5. The symptom/amplitude time lag metric was used to define activity-relieved and post-gastric symptom profiles, defined as negative (< -0.25) or positive (>0.25) average difference between the cumulative distribution functions of the symptom and amplitude curves. Conclusions & InferencesStandardized quantification of symptom profiles in relation to a meal-stimulus and gastric amplitude offer a novel classification scheme based on gastroduodenal physiology.

Background & Aims: The association between upper gastrointestinal (GI) symptoms and delayed gastric emptying time (GET) is debated. This study utilized Body Surface Gastric Mapping (BSGM) and the 'Auckland Classification' BSGM phenotyping scheme to investigate whether symptom associations with GET vary across different mechanistic phenotypes. Methods: A pooled analysis was performed on two prospective datasets of 194 patients with chronic upper GI symptoms. Participants underwent simultaneous BSGM (Gastric Alimetry) and gastric emptying testing (breath test or scintigraphy). Validated time-of-test symptom profiling was recorded at 15-minute intervals using 0-10 Likert-type scales. Patients were classified: 'Spectral Abnormal' (abnormal electrophysiology), 'Sensorimotor' (symptoms correlate with gastric electrical amplitude), 'Continuous' (symptoms uncorrelated), and 'NA' (no phenotype). Results: In the analyzed cohort, 24% had delayed GET. Overall, delayed GET was associated with a higher total symptom burden (15.6 delayed vs. 8.8 normal, p=0.006; r=0.30, p<0.001), specifically postprandial fullness (p=0.004) and early satiation (p=0.015). However, associations varied significantly by phenotype. In the 'Sensorimotor' phenotype, nausea was associated with delayed GET (4.9 vs. 1.0, p=0.027; r=0.59, p=0.009), while total symptom burden was 23.3 vs. 8.4 (p=0.135). Conversely, patients with 'Continuous' or 'Spectral Abnormal' phenotypes, or who were unclassified, showed no symptom associations. Conclusions: Delayed GET is weakly associated with an increased burden of upper GI symptoms. However, gastroduodenal disorders are heterogeneous, such that phenotyping reveals this association to be exclusive to patients with a 'Sensorimotor' phenotype. These results could improve targeting of therapies that address gastric emptying.

Background and aimsChronic gastroduodenal symptoms may be associated with psychological factors; however, recent evidence suggests these associations vary by previously undetermined disease factors. Body surface gastric mapping (BSGM) is a non-invasive diagnostic method integrating high-resolution myoelectrical measurement and validated symptom profiling. This cross-sectional study investigated associations between psychological factors and BSGM phenotypes. MethodsPatients from the general community meeting the Rome IV Criteria for functional dyspepsia or chronic nausea and vomiting syndrome underwent BSGM using Gastric Alimetry(R). The test protocol included a 30-min fasting baseline, 482 kCal meal, and 4-hr postprandial recording. Measures of depression, anxiety, stress, and quality of life were assessed at baseline, and symptoms were logged throughout the test. BSGM phenotypes were classified using established rule-based criteria. ResultsAmong 278 patients (mean age 39.5, 15-88; 77% female), clinical diagnoses of depression (45%) and anxiety (46%) were common. Depression, anxiety, and stress measures were positively associated with symptom severity; however, these associations varied substantially by BSGM phenotype. Abnormal rhythm stability predicted higher depression (B=0.35, p=.044) and stress (B=1.48, p=.026). Among patients with normal spectral metrics, continuous symptoms predicted higher levels of depression (B=0.42, p=.003), anxiety (B=0.30, p=.045), and stress (B=1.43, p=.008), and worse quality of life (B=-0.57, p< .001); while sensorimotor symptoms predicted higher anxiety (B=0.46, p=.029) and worse quality of life (B=-0.49, p=.033). ConclusionThis study confirms significant connections between gastroduodenal symptoms and mental health, but refines these associations to specific BSGM phenotypes. Individuals exhibiting normal spectral metrics alongside continuous or sensorimotor symptoms may particularly benefit from integrated psychological interventions.

BackgroundSleeve gastrectomy is an effective bariatric procedure, however may lead to persistent symptoms without obvious mechanical cause. The normal gastric pacemaker region, which lies on the greater curvature of the corpus, is resected in sleeve gastrectomy, however, the electrophysiological consequences are not adequately defined. This study assessed these impacts and associations with symptoms and quality of life (QoL), using non-invasive gastric mapping. MethodsPatients with previous sleeve gastrectomy underwent body surface gastric mapping (Gastric Alimetry, New Zealand), comprising 30-minute fasting baseline and 4-hr post-prandial recordings. Analysis encompassed Principal Gastric Frequency (PGF), BMI-adjusted amplitude, Gastric Alimetry Rhythm Index (GA-RI), with comparison to reference intervals and matched controls. Symptoms were evaluated using a validated App and questionnaires. Results38 patients (median 36 months post-surgery; range 6-119 months) and 38 controls were recruited. 35/38 patients had at least one abnormal parameter, typically reduced frequencies (2.3{+/-}0.34 vs controls 3.08{+/-}0.21; p<0.001) and amplitudes (14.8{+/-}6.9 vs 31.5{+/-}17.8; p<0.001). Patients exhibited higher symptoms and lower QoL (PAGI-SYM 20 vs controls 7, p<0.001; PAGI-QOL 27 vs 136, p<0.001). Gastric amplitude and GA-RI correlated positively with bloating (r=0.71, p<0.001 and r=0.60, p=0.02) while amplitude correlated negatively with heartburn (r=-0.46, p=0.03). Lower gastric amplitudes also correlated with greater weight loss (r=-0.45; p=0.014). ConclusionSleeve gastrectomy modifies gastric electrophysiology due to pacemaker resection, with variable remodelling. Substantial reductions in gastric frequency and amplitude occur routinely after surgery, and specific relationships between post-sleeve gastric amplitude, symptoms of heartburn and bloating, and weight loss are identified.

BackgroundGastric Alimetry is a new diagnostic tool using non-invasive gastric electrical mapping and symptom logging to identify patient subgroups. This study aimed to propose an initial framework for Gastric Alimetry implementation in the routine management of gastroduodenal disorders, and assess its impact on diagnosis and management. MethodsGastric Alimetry using standard tests (30-min fasted, ~480kCal meal, followed by 4-hr postprandial recording with concurrent symptom logging) was applied to patients presenting with gastroduodenal symptoms. ResultsOverall, 50 patients were evaluated with Gastric Alimetry. The test aided management decisions in 78% of patients (39/50) and aided a change in diagnosis in 40% (20/50), predominantly from a motility disorder to disorders of gut-brain interaction (DGBI). Changes in invasive nutritional support occurred in 18% (9/50). ConclusionGastric Alimetry impacted care in most patients in this first series. Further work to inform clinical utility is now a priority.

MessageGastric per oral endoscopic myotomy (GPOEM) is a promising therapy for refractory gastroparesis, but patient selection remains challenging. We evaluated body surface gastric mapping (BSGM) phenotypes to predict treatment response. Patients were recruited at Kings College Hospital (Nov 2022-July 2025). BSGM comprised 30-min fasting, standardized nutrient drink with oatmeal bar (482 kcal), and 4-h postprandial recording. Success was defined as [&ge;]1 point reduction in Gastroparesis Cardinal Symptom Index or complete symptom resolution at follow-up. Overall, 53% responded, including all patients with dysrhythmic or continuous phenotypes. Higher gastric frequencies predicted non-response (p=0.03).

BackgroundAdverse gastric symptoms persist in up to 20% of fundoplication surgeries completed for gastroesophageal reflux disease, causing significant morbidity, and driving the need for revisional procedures. Non-invasive techniques to assess the mechanisms of persistent postoperative symptoms are lacking. We aimed to investigate gastric myoelectrical abnormalities and symptoms in patients after fundoplication using a novel non-invasive body surface gastric mapping (BSGM) device. MethodsPatients with previous fundoplication surgery and ongoing significant gastroduodenal symptoms, and matched controls were included. BSGM using Gastric Alimetry (Alimetry, New Zealand) was employed, consisting of a high resolution 64-channel array, validated symptom-logging App, and wearable reader. Results16 patients with significant chronic symptoms post-fundoplication were recruited, with 16 matched controls. Overall, 6/16 (37.5%) patients showed significant spectral abnormalities defined by unstable gastric myoelectrical activity (n = 2), abnormally high gastric frequencies (n = 3) or high gastric amplitudes (n = 1). Those with spectral abnormalities had higher Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index scores (3.2 [2.8 to 3.6] vs 2.3 [2.2 to 2.8]; p =0.024). 7/16 patients (43.8%) had Gastric Alimetry tests suggestive of gut-brain axis contributions, and without myoelectrical dysfunction. Increasing Principal Gastric Frequency deviation, and decreasing Rhythm Index were associated with symptom severity (r>0.40, p<0.05). ConclusionA significant number of patients with persistent post-fundoplication symptoms display abnormal gastric function on Gastric Alimetry testing, which correlates with symptom severity. These findings advance the pathophysiological understanding of post-fundoplication disorders which may inform diagnosis and patient selection for medical therapy and revisional surgery.

BackgroundPatients with chronic gastroduodenal disorders present with overlapping symptoms. Guidelines emphasize symptom-based criteria, but clinical evaluations are inconsistent due to non-standardized assessments and recall bias. Gastric Alimetry(R) is a non-invasive test of gastric function enabling real-time symptom evaluation via a standardized app. MethodsParticipants meeting Rome IV criteria for functional dyspepsia (FD) and/or chronic nausea and vomiting syndrome (CNVS) underwent a Gastric Alimetry test, including a meal challenge, with symptoms recorded every 15 minutes in the app. Based on time-of-test symptoms, four novel scores were developed: nausea/vomiting, postprandial distress, epigastric pain, and burning/reflux. Group differences were analyzed using pairwise t-tests, and Rome IV classifications were predicted via logistic regression. Remote moderated usability testing assessed score acceptability. Key ResultsAmong 109 participants (79% female, 18-80 yrs), 54 met criteria for CNVS with/without FD, 41 for postprandial distress syndrome (PDS) only, and 14 for epigastric pain syndrome (EPS) with/without PDS. Symptom scores aligned with Rome IV classifications (p<.05 for CNVS and EPS). Logistic regression showed good discrimination for CNVS (AUC=0.85) and EPS (AUC=0.80), and moderate discrimination for PDS (AUC=0.68). Usability testing confirmed clinical utility and ease of use. Conclusions & InferencesGastric Alimetry symptom scores align with Rome IV classifications, with real-time patient-reported snapshots accurately reflecting chronic symptom burden. These scores provide a clinically applicable diagnostic tool alongside simultaneous physiological gastric function assessments. Key PointsO_LIFour novel Gastric Alimetry symptom scores summarize the relative severity of symptoms in subgroups aligned with Rome IV classifications. C_LIO_LIThe proposed time-of-test symptom scores showed moderate-to-good ability to predict diagnoses made using the Rome IV criteria. C_LIO_LIUsability testing with eight clinicians showed that the scores provided an easy-to-use and clinically useful tool to complement diagnosis of gastroduodenal disorders. C_LI

IntroductionAchalasia is a rare primary esophageal motility disorder characterized by impaired lower esophageal sphincter relaxation and dysphagia. Laparoscopic Heller myotomy (LHM) has long been the standard treatment, while peroral endoscopic myotomy (POEM) has emerged as a minimally invasive alternative. Comparative evidence from randomized controlled trials (RCTs) remains limited, and outcomes such as gastroesophageal reflux disease (GERD) and clinical remission require clarification. MethodsWe systematically searched PubMed, Embase, Cochrane CENTRAL, and Web of Science to September 2025 for RCTs comparing POEM and LHM in adult patients with achalasia. Data on demographics, previous treatment, dysphagia improvement, GERD incidence, clinical remission, and mortality were extracted. Pooled odds ratios (OR) with 95% confidence intervals (CI) were calculated using a random-effects model in Stata 18. ResultsSeven RCTs involving 900 patients (465 POEM; 465 LHM) were included. Dysphagia improvement was similar between groups (log OR 0.14; 95% CI -0.32 to 0.59; p = 0.55). GERD incidence was higher after POEM but not statistically significant (log OR 0.59; 95% CI -0.08 to 1.25; p = 0.08). Clinical remission showed a non-significant trend favoring POEM (log OR 0.39; 95% CI -0.06 to 0.84; p = 0.09). Reduction in pH levels significantly favored LHM (log OR 0.75; 95% CI 0.18 to 1.33; p = 0.01). No mortality was reported. ConclusionPOEM and LHM provide comparable dysphagia relief and clinical remission in achalasia. However, POEM is associated with higher GERD risk, particularly on pH monitoring. Treatment choice should balance efficacy against reflux risk, with careful long-term follow-up.

ObjectiveThis study examined the impact of anxiety, depression, and sleep quality on mean nocturnal baseline impedance (MNBI), post-reflux swallow-induced peristaltic wave index (PSPW-I), and esophagogastric junction contractile index (EGJ- CI) in patients with refractory gastro-esophageal reflux disease (rGERD), functional heartburn (FH), and reflux hypersensitivity (RH). MethodsRetrospective analysis included 75 patients aged 18-70 with persistent reflux symptoms despite 8 weeks of proton pump inhibitor (PPI) therapy. Evaluations included esophagogastroduodenoscopy, high-resolution manometry, 24-hour pH- impedance monitoring, and psychological assessments (SAS, SDS, PSQI). Patients were grouped into rGERD, FH, and RH. MNBI, PSPW-I, and EGJ-CI were compared, and correlations with psychological and sleep parameters were analyzed. ResultsDistal MNBI was significantly lower in rGERD (1177.91 {+/-} 707.22 {Omega}) vs. FH (1995.77 {+/-} 476.02 {Omega}) and RH (2062.35 {+/-} 509.93 {Omega}) (P < 0.001). Anxiety prevalence was 85.7% in rGERD, 64.7% in FH, and 67.5% in RH (P = 0.302); depression affected 78.6% of rGERD, 70.8% of FH, and 72.9% of RH patients (P = 0.942). Poor sleep quality was present in >80% of all groups. PSPW-I negatively correlated with anxiety (r = -0.181, P < 0.05) and depression (r = -0.158, P < 0.05), as did proximal MNBI with depression (r = -0.175, P < 0.05). A distal MNBI cutoff of 1531 {Omega} distinguished rGERD from FH/RH with 71.4% sensitivity and 87.5% specificity (AUC = 0.80). ConclusionAnxiety, depression, and poor sleep quality impair PPI efficacy and worsen esophageal acid clearance. Distal MNBI effectively differentiates rGERD from FH/RH. Addressing psychological and sleep disturbances may improve treatment outcomes in refractory reflux patients.

Irritable Bowel Syndrome (IBS) is a highly prevalent, commonly diagnosed gastrointestinal disorder of gut-brain interaction (DGBI) that causes substantial physical, psychological, and financial burden. The role of abnormal motility and altered autonomic nervous system function, and their interplay, remains to be fully understood. Here we present a non-invasive method using body surface electrical recordings to concurrently quantify meal-response colonic motility and heart rate variability (HRV). We demonstrate the practical utility of this new technique in a pilot study comparing colonic motility and autonomic nervous system (ANS) function in IBS patients (n=14) and healthy controls (HC; n = 22). The study protocol included a 2-3 hr body-surface electrical recording with 60-90 minutes each of pre- and post- meal epochs. Colonic motility was markedly increased in the subset of IBS patients experiencing moderate-to-severe symptoms during the study, compared to IBS no or mild symptom groups and healthy controls. HRV metrics in IBS patients showed substantial baseline shifts with decreased vagal and increased sympathetic input, with blunted autonomic meal responses compared to HC. Newly introduced dynamic trajectory maps revealed pronounced colon motility-vagal dysregulation in high symptom IBS patients but not mild or no symptom groups. These results indicate altered autonomic-motility interaction as a potential mechanism of symptom genesis in IBS patients. This technology platform offers an easy-to-apply, non-invasive tool for larger scale investigations of gut and autonomic nervous system function in healthy and gastrointestinal disease cohorts.

BackgroundWhile most gastric bypass patients recover well, some experience long-term complications, including nausea, pain, stricture, and dumping. This study aimed to evaluate symptoms and quality of life (QoL) together with remnant stomach function using the novel Gastric Alimetry(R) system. MethodGastric bypass and conversion-to-bypass patients were recruited. The Gastric Alimetry system (Auckland, NZ) was employed, comprising a high-resolution electrode Array, and validated symptom logging App. The protocol comprised 30-minute fasting baseline, a 218kCal meal stimulus, and 4-hours of post-prandial recordings. Symptoms and QoL were evaluated using validated PAGI questionnaires. Remnant gastric electrophysiology evaluation included frequency, BMI-adjusted amplitude, and Gastric Alimetry Rhythm Index (GA-RI; reflecting pacemaker stability), with comparison to matched controls. Results38 participants were recruited with mean time from bypass 46.8 {+/-} 28.6 months. One third of patients showed moderate to severe post-prandial symptoms, with patients PAGI-SYM 28 {+/-} 19 vs controls 9 {+/-} 17; PAGI-QoL 37 {+/-} 31 vs 135 {+/-} 22 (p<0.01). Remnant gastric function was markedly degraded shown by undetectable frequencies in 84% (vs 0% in controls), and low GA-RI (0.18 {+/-} 0.08 vs 0.51 {+/-} 0.22 in controls; p<0.0001). Impaired GA-RI and amplitude were correlated with worse PAGI-SYM and PAGI-QOL scores. ConclusionOne third of post-bypass patients suffered significant upper GI symptoms with reduced QoL. The bypassed remnant stomach shows highly deranged electrophysiology, reflecting disuse degeneration. These derangements correlated with QoL, although causality was not addressed.

IntroductionOesophagectomy is a complex procedure performed for malignant and benign conditions. Post-oesophagectomy conduit dysfunction is common, which can occur for several reasons including conduit dysmotility. However, reliable tools for evaluating conduit motility are lacking. A non-invasive device for gastric electrical mapping was recently developed to evaluate gastric electrical activity and function. This study aimed to assess the feasibility of BSGM in the post-oesophagectomy stomach. MethodsOesophagectomy patients from Auckland, New Zealand, were recruited. The Gastric Alimetry System(R) (New Zealand) was employed, comprising a stretchable array (8x8 electrodes), a wearable Reader, and validated iOS app for symptom logging. The protocol comprised a 30-minute baseline, a meal challenge, then 4 hours of post-prandial recordings. Analysis encompassed Principal Gastric Frequency, BMI-adjusted amplitude, Gastric Alimetry Rhythm Index (indicating rhythm stability), meal response, and symptoms. Adverse events were recorded. Results6 patients were recruited and gastric activity was successfully captured in all except one with the colonic interposition (negative control). Four patients showed abnormalities indicating post-operative gastric hypofunction: four with low or abnormal frequency (<2.65 cycles/min), three with low amplitude (<22V), two with low GA-RI (<0.25) and one with a reduced meal response. One patient had significant symptoms (nausea, early satiation) who demonstrated marked hypomotility in all four of these domains. No adverse events occurred. ConclusionGastric Alimetry is a safe and feasible technique to non-invasively assess gastric conduit motility following oesophagectomy. Parameters may need adjustment for post-surgical anatomy. Clinical studies assessing the role in diagnosis and therapy can be advanced.

BackgroundThe present report examines gastric pH from normal subjects and different gastroesophageal reflux disease (GERD) phenotypes to compare the distributions of gastric pH values and of changes in gastric acid concentrations to those reported previously for esophageal pH from the same groups of subjects. I also examined total esophageal acidity as a function of total gastric acidity in the different groups of subjects. MethodsI analyzed 24-hour gastric and esophageal pH recordings from normal subjects and subjects with a particular GERD phenotype to calculate total integrated acidity and total time pH<4. I also examined gastric pH recordings for the distributions of gastric pH values and the distributions of changes in gastric acidity. ResultsThere were different distributions for gastric pH, but virtually identical distributions of changes in gastric acid concentrations in the different groups of subjects. There was a significant positive relationship between total integrated esophageal acidity and total integrated gastric acidity in different GERD phenotypes, but not in normal subjects. The slope of the line relating integrated esophageal acidity to gastric acidity correlated directly with the responses of different GERD phenotypes to PPI treatment reported previously by others. ConclusionsIt seems possible esophageal acidity and gastric acidity can influence each other and by so doing account for the variation in the differences in the distributions of values of pH and acid concentrations among normal subjects and different GERD phenotypes. Furthermore, the strength of the relationship between esophageal and gastric acidity can determine the response to PPI treatment.

Objectives. To compare the efficacy and safety of invasive sacral neuromodulation (SNM) and noninvasive enteral neuromodulation (ENM) in children with refractory gastrointestinal motility disorders (GMD). Materials and Methods. This prospective interventional trial enrolled pediatric patients with GMD between 2019 and 2024 at a single tertiary referral center. Children with inflammatory bowel disease or mechanical causes of GMD were excluded. Participants received either SNM via an implanted device or ENM via surface electrodes. Stimulation was delivered at 14 Hz, 210 s pulse width, with individualized intensity (median 1.0 mA for SNM; 6.0 mA for ENM). Primary outcomes were abdominal pain, fecal incontinence, defecation frequency, and stool consistency. Treatment success was defined as clinically significant improvement in at least two of these four domains. Quality of life was assessed at baseline and 12 weeks. Safety outcomes were monitored over a 12-month follow-up. Results. Of 70 eligible patients, 48 completed the study (18 SNM; 30 ENM). Diagnoses included Hirschsprung disease, functional constipation, and congenital neuronal malformations. Severe comorbidities were more frequent in the SNM group (45%) than the ENM group (3%; P = .0018). Treatment success was observed in 80% of ENM and 83% of SNM patients (P = 1.00). No significant differences were found between groups for individual outcomes. No major complications occurred. Minor adverse events were comparable (ENM 27% vs SNM 17%; P = .50). Conclusions. Both SNM and ENM are effective and safe options for treating pediatric GMD and may be considered within a multimodal therapeutic approach.