Clinical utility of electrogastrography and the water load test in patients with upper gastrointestinal symptoms

Pilot study of a water load test as a measure of gastric interoception in anorexia nervosa

PURPOSE

Research and clinical experience suggest that individuals with anorexia nervosa (AN) have deficits in gastric interoception, which has been hypothesized to maintain restrictive eating. Behavioral water load tasks (WLTs) have the capability to noninvasively assess gastric interoception; however, to date, no studies have examined WLTs in AN. Thus, the present proof-of-concept pilot study explored the preliminary validity of a WLT in individuals with AN.

METHODS

Participants were n = 10 individuals with AN and n = 10 matched-control women (CW). Participants completed self-report questionnaires before and after a WLT, in which participants were asked to drink water until "completely full".

RESULTS

Participants with AN drank significantly less water than CW (AN = 240(109.14) milliliters (ml), CW = 398.00(149.21) ml, p = 0.02, Cohen's d = 1.21), but reported greater increases in negative affect pre- to-post-WLT (p = 0.04, partial eta² = 0.21). Correlations between WLT performance and interoceptive sensibility in AN and CW participants supported the convergent validity of the WLT.

CONCLUSION

Preliminary results support the potential utility of the WLT as a behavioral measure of gastric interoception in patients with AN. Future research should examine how response to the WLT changes over the course of intervention and how results are related to treatment outcome.

LEVEL OF EVIDENCE

Level IV: Evidence obtained from multiple time series analysis such as case studies. (NB: Dramatic results in uncontrolled trials might also be regarded as this type of evidence).

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.

The water load test in school children and adolescents with functional gastrointestinal disorders

BACKGROUND/AIMS

We hypothesize that patients with functional gastrointestinal disorders (FGID) drink less water volume than healthy subjects during water load test. We evaluated and compared the water load test in students with and without FGID using the Rome III questionnaire.

METHODS

We performed the water load test in 142 students from two schools in Colombia. Students were diagnosed using the Spanish version of the Rome III questionnaire. Students drank water ad libitum for 3 min or until pain, satiety, or vomiting occurred. We correlated anthropometric variables with water volumes drunk. We recorded symptoms like pain and nausea, before and after the water load test.

RESULTS

We evaluated 142 students, with a mean age of 12.1 ± 0.2 years and 59.9% girls. Mean water volume drunk was 459 ± 22 mL. There was no significant difference between water volume drunk by students with and without FGID (466 ± 36 vs. 453 ± 27 mL, p = 0.108). We found a significant correlation between water volume drunk and gender, age, weight, height, and body mass index.

CONCLUSIONS

Students with and without FGID ingest similar volumes of water. Test adverse effects are minimal, and the test is safe to perform and well tolerated.

Reference values for the water load test in healthy school children and adolescents

BACKGROUND AND STUDY AIM

The water load test (WLT) is an easy and cheap tool, useful in evaluating gastric accommodation and visceral hypersensitivity. This test can be used in diagnosing functional gastrointestinal disorders, like functional dyspepsia. Our main aim was to propose reference values for the WLT. Our secondary aim was to correlate the water volume drunk with the students' gender, age, and anthropometric measures.

PATIENTS AND METHODS

We performed the WLT in students aged 8 to 17 years. Students drank water ad libitum for 3 minutes or until pain, satiety or vomiting occurred. We correlated anthropometric variables with water volumes drunk. Upper and lower limit for the maximum tolerated volume were calculated as the 5th and 95th percentile. Pain and nausea were recorded before and after the test.

RESULTS

We evaluated 99 students, with a median age (inter quartile range) of 11 years 10-13 years) and 55.6 % were girls. Median water volume drank was 380 ml (190-540 ml). Boys (523 ml, interquartile range : 275-760 ml) drank more water than girls (380 ml, interquartile range : 190-570 ml) (p = 0.016). There was a significant correlation between water volume drank and students´ age, weight, height, and body mass index. Of the students that completed the WLT, 22.2 % had nausea and 30.3 % had mild abdominal pain after the test.

CONCLUSIONS

We proposed reference values for the WLT in children aged 8 to 17 years. Adverse effects are minimal, it is safe to perform, and well tolerated.

Osteopathic Manipulative Treatment Alters Gastric Myoelectric Activity in Healthy Subjects

Objectives: It is unclear whether osteopathic manipulative treatment (OMT) affects gastric myoelectric activity (GMA), an index of gastric motility. We hypothesized that OMT significantly alters power spectral density (PSD) analyses of electrogastrography (EGG) recordings, an index of GMA, compared with time control OMT. Design: GMA data were obtained from nine subjects before and after OMT and time control on separate days in a cross-over design. Fifteen-minute EGG recordings were obtained before and after each intervention and after a water challenge (WC). Percent power in the normogastric range (PPN) was estimated from PSD analyses. Absolute percent change of PPN and dominant frequency (DF) from baseline to postintervention and baseline to post-WC was computed and compared using two-way repeated-measures ANOVA. Results: OMT altered PPN versus time control (time control: 5.3% ± 1.2%; OMT: 24.5% ± 4.5%; p = 0.015). WC altered PPN compared with time control (post-time control ΔPPN: 5.3% ± 1.2%; post-drink ΔPPN: 30.3% ± 7.2%; p < 0.01). However, WC did not alter PPN with prior OMT treatment (post-OMT ΔPPN: 24.5% ± 4.5%; post-WC ΔPPN: 19.4% ± 5.6%; p = 0.47). Nevertheless, OMT reduced the rate of change for DF compared with time control (WC post-time control: 37.9% ± 7.4%; WC post-OMT: 20.0% ± 5.9%; p = 0.02). Conclusions: We conclude that (1) OMT significantly alters GMA compared with time control and that (2) OMT reduces the rate of change in the frequency response to WC within the normal frequency range of 2-4 cycles per minute, indicating a physiological effect.

Water Load Test in Childhood Functional Abdominal Pain: No Relation to Food Intake and Nutritional Status

This cross-sectional study evaluates the relations between the water load test in childhood functional gastrointestinal disorders with food intake and nutritional status. Patients with functional dyspepsia required a lower maximum water intake to produce fullness (n = 11, median = 380 mL) than patients with irritable bowel syndrome (n = 10, median = 695 mL) or functional abdominal pain (n = 10, median = 670 mL) (P < 0.05). Among patients who ingested ≤560 mL (n = 17) or >560 mL (n = 14) in the water load test, there was no relation between the maximum drinking capacity and food intake, body mass index, or height.

Current status of multichannel electrogastrography and examples of its use

Electrogastrography (EGG) is a non-invasive diagnostic motility for recording gastric myoelectrical activity. Gastric myoelectrical activity was first recorded in 1922. Advances in recording equipment enabled widespread use of cutaneous EGG after 1985. Later, introduction of multichannel EGG (M-EGG) enabled measurement of electrical activity transmission. At present, M-EGG findings are used as objective indicators of gastric motility disorders caused by various diseases. EGG measures two categories of gastric electrical activity: electrical response activity, or spike potentials; and electrical control activity, or slow waves. The appearance of abnormal rhythmic electrical activity is indicative of abnormalities in gastric motility. The normal frequency range of gastric electrical activity (normogastria) is around 3 cycles per min. Multiple EGG parameters assist in the assessment of gastric myoelectrical activity, and significant correlations between EGG and other gastric motility tests have been demonstrated in many studies. In Japan, however, EGG remains in the exploratory stage, and its clinical use is limited. There are large variations in procedures and systems used in previous studies, thus there is a need for standardization of EGG procedures and technical terminology. Here, we outline the current status of EGG and report the M-EGG procedures used in our department in addition to our M-EGG findings.

The abstract of this manuscript was presented during an educational seminar titled "Current status of gastrointestinal motility tests and keys for immediate implementation" at the 54th Annual Meeting of the Japan Society of Smooth Muscle Research

Sensitivity and specificity of hypnosis effects on gastric myoelectrical activity

OBJECTIVES

The effects of hypnosis on physiological (gastrointestinal) functions are incompletely understood, and it is unknown whether they are hypnosis-specific and gut-specific, or simply unspecific effects of relaxation.

DESIGN

Sixty-two healthy female volunteers were randomly assigned to either a single session of hypnotic suggestion of ingesting an appetizing meal and an unappetizing meal, or to relax and concentrate on having an appetizing or unappetizing meal, while the electrogastrogram (EGG) was recorded. At the end of the session, participants drank water until they felt full, in order to detect EGG-signal changes after ingestion of a true gastric load. During both conditions participants reported their subjective well-being, hunger and disgust at several time points.

RESULTS

Imagining eating food induced subjective feelings of hunger and disgust as well as changes in the EGG similar to, but more pronounced than those seen with a real gastric water load during both hypnosis and relaxation conditions. These effects were more pronounced when imagining an appetizing meal than with an unappetizing meal. There was no significant difference between the hypnosis and relaxation conditions.

CONCLUSION

Imagination with and without hypnosis exhibits similar changes in subjective and objective measures in response to imagining an appetizing and an unappetizing food, indicating high sensitivity but low specificity.

Evaluation of electrical activity after vagus nerve-preserving distal gastrectomy using multichannel electrogastrography

BACKGROUND

Multichannel electrogastrography (M-EGG) can be used to evaluate gastrointestinal motility. The myoelectric activity of the remnant stomach after surgery has not been measured by M-EGG. This study examined whether myoelectric activity varied with surgical technique and compared vagus nerve-preserving distal gastrectomy (VP-DG) with standard distal gastrectomy without vagus nerve preservation (DG). Furthermore, we examined the relationship between the M-EGG findings and patients' postoperative symptoms.

METHODS

Twenty-six patients who underwent VP-DG, 20 who underwent DG, and 12 healthy volunteers as controls were examined with M-EGG. The Gastrointestinal Symptom Rating Scale (GSRS) was used to assess postoperative symptoms.

RESULTS

Longer periods of normal gastric function (normogastria, 2.0-4.0 cycle min(-1)) were detected in channel 1 in the VP-DG group than in the DG group in either the fasted or fed state (P<0.05). The percentage of slow wave coupling (%SWC) in the fed state correlated negatively with GSRS scores (reflux, r=-0.59, P=0.02; abdominal pain, r=-0.51, P=0.04, indigestion, r=-0.59, P=0.02 and total score, r=-0.75, P=0.02).

CONCLUSIONS

Slow waves can be recorded non-invasively using M-EGG in the remnant stomach following gastrectomy. The VP-DG group showed better preserved gastric myoelectric activity than the DG group, and the %SWC showed a significant negative correlation with scores of GSRS (reflux, abdominal pain, indigestion and total score) in the VP-DG group.

Preclinical electrogastrography in experimental pigs

Surface electrogastrography (EGG) is a non-invasive means of recording gastric myoelectric activity or slow waves from cutaneous leads placed over the stomach. This paper provides a comprehensive review of preclinical EGG. Our group recently set up and worked out the methods for EGG in experimental pigs. We gained our initial experience in the use of EGG in assessment of porcine gastric myoelectric activity after volume challenge and after intragastric administration of itopride and erythromycin. The mean dominant frequency in pigs is comparable with that found in humans. EGG in experimental pigs is feasible. Experimental EGG is an important basis for further preclinical projects in pharmacology and toxicology.