Gastric myoelectric activity in older adults treated with cisapride for gastro-oesophageal reflux disease

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.

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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.

Electrogastrography: methodology, validation and applications

Electrogastrography (EGG) is a non-invasive method for the measurement of gastric myoelectrical activity. It was first discovered in 1921 and popularized in 1990s. EGG is attractive because it is non-invasive. However, due to its non-invasive nature, there have also been controversies regarding validity and applications of EGG. The aim of this review is to discuss the methodologies, validation and applications of EGG. Pros and cons of EGG will also be discussed in detail. First, the gastric slow wave and its correlation with gastric motility are presented. The association between gastric dysrhythmia and impaired gastric motility is reviewed. Secondly the method for recording the electrogastrogram is presented in detail and pitfalls in the recording and analysis of EGG are discussed. Thirdly, findings reported in the literature demonstrating the accuracy of EGG in recording gastric slow waves and gastric dysrhythmia are reviewed and discussed. The correlation of the electrogastrogram with gastric contraction is carefully discussed. Finally, applications of EGG in a few major areas are reviewed.

Electrogastrography: methodology, validation and applications

Electrogastrography (EGG) is a non-invasive method for the measurement of gastric myoelectrical activity. It was first discovered in 1921 and popularized in 1990s. EGG is attractive because it is non-invasive. However, due to its non-invasive nature, there have also been controversies regarding validity and applications of EGG. The aim of this review is to discuss the methodologies, validation and applications of EGG. Pros and cons of EGG will also be discussed in detail. First, the gastric slow wave and its correlation with gastric motility are presented. The association between gastric dysrhythmia and impaired gastric motility is reviewed. Secondly the method for recording the electrogastrogram is presented in detail and pitfalls in the recording and analysis of EGG are discussed. Thirdly, findings reported in the literature demonstrating the accuracy of EGG in recording gastric slow waves and gastric dysrhythmia are reviewed and discussed. The correlation of the electrogastrogram with gastric contraction is carefully discussed. Finally, applications of EGG in a few major areas are reviewed.

Electrogastrography associated with symptomatic changes after prokinetic drug treatment for functional dyspepsia

AIM: To evaluate the effect of prokinetic drugs on electrogastrography (EGG) parameters according to symptomatic changes in patients with functional dyspepsia (FD).

METHODS: Seventy-four patients with FD were prospectively enrolled in this study between December 2006 and December 2010. We surveyed the patients using a questionnaire on dyspeptic symptoms before and after an 8-wk course of prokinetic drug treatment. We also measured cutaneous pre-prandial and post-prandial EGG recordings including percentage of gastric waves (normogastria, bradygastria, tachygastria), dominant frequency (DF), dominant power (DP), dominant frequency instability coefficient (DFIC), dominant power instability coefficient (DPIC), and the ratio of post-prandial to fasting in DP before and after the 8-wk course of prokinetic drug treatment.

RESULTS: Fifty-two patients (70%) achieved symptomatic improvement after prokinetic drug treatment. Patients who had normal gastric slow waves showed symptom improvement group after treatment. Post-prandial DF showed a downward trend in the symptom improvement group, especially in the itopride group. Post-prandial DP was increased regardless of symptom improvement, especially in the itopride group and mosapride group. Post-prandial DFIC and DPIC in the symptom improvement group were significantly increased after the treatment. The EGG power ratio was increased after treatment in the symptom improvement group (0.50 ± 0.70 vs 0.93 ± 1.77, P = 0.002), especially in the itopride and levosulpiride groups.

CONCLUSION: Prokinetics could improve the symptoms of FD by regulating gastric myoelectrical activity, and EGG could be a useful tool in evaluating the effects of various prokinetics.

Impact of lumbar kyphosis on gastric myoelectrical activity and heart rate variability in a model using flexion posture in healthy young adults

Relationship between lumbar kyphotic deformity and gastroesophageal reflux disease has been indicated in recent years. But it remains unclear whether kyphotic deformity of the lumbar vertebrae affects gastric motility. Healthy young adults (n = 20) were analyzed by recording the electrogastrography (EGG) and heart rate variability (HRV) before and after meal with flexion and neutral postures. Dominant power (DP) and dominant frequency (DF) of EGG and low frequency (LF) and high frequency (HF) of HRV were analyzed in blocks of 10 minutes' duration. In neutral posture, DPs of all postprandial durations were significantly higher than those during fasting in two channels (P < 0.05, P < 0.01). However, in flexion posture, only DP at postprandial 20 (10-20 minutes after eating) in a channel was significantly higher than that during fasting (P < 0.05). DF in neutral posture was significantly higher than that in flexion posture at postprandial 20 in a channel (P < 0.05). The standard deviation of DF at postprandial 10 in flexion posture was significantly higher than that during fasting in a channel (P < 0.05). LF/HF in neural posture was significantly higher than that in flexion posture at postprandial 10 (P < 0.05). These findings suggest that inhibition of stomach myoelectrical activity was induced in the flexion posture in this lumbar kyphotic model, and autonomic activity as assessed by HRV did not accord with that expected from EGG.

Impaired gastric motility and its relationship to reflux symptoms in patients with nonerosive gastroesophageal reflux disease

BACKGROUND

More than half of patients with refluxrelated symptoms have no endoscopic evidence of mucosal breaks. These patients are considered to have nonerosive gastroesophageal reflux disease (NERD). The pathogenesis of NERD may be multifactorial, but the role played by gastric motility in symptom generation in patients with NERD has not been examined. In this study, we elucidate gastric motility in patients with NERD and the efficacy of a prokinetic agent in the treatment of NERD.

METHODS

Gastric motility was evaluated with electrogastrography (EGG) and by measurement of gastric emptying using the acetaminophen method in 26 patients with NERD and in 11 matched healthy controls. NERD patients were treated with a prokinetic agent (mosapride 15 mg, orally three times daily) for a period of 4 weeks, after which gastric motility was measured again.

RESULTS

Compared with the healthy controls, the NERD patients showed a significantly lower percentage of normogastria, a lower power ratio in EGG, and delayed gastric emptying. Ten patients had normal gastric motor function (group A), and 16 showed abnormalities of either gastric myoelectrical activity or gastric emptying (group B). After treatment with mosapride, gastric motility improved significantly in both groups of patients compared with pretreatment values. The subjective assessment by the patient after the treatment was improved in 20.0% of group A versus 62.5% of group B patients (P < 0.05).

CONCLUSIONS

Gastric hypomotility appears to be an important factor in reflux symptom generation in some NERD patients.

Analysis of the electrogastrogram using discrete wavelet transform and statistical methods to detect gastric dysrhythmia

Electrogastrography (EGG) is a method of recording stomach electrical activity from cutaneous electrodes placed on the abdominal surface. Compared with other electrophysiological measurements, such as electrocardiography, the progress of the applicability of the EGG has been very slow. Unlike imaging or manometrical studies, stomach motility disorders are not diagnosed based only on abnormal EGG parameters. Limitations of EGG recording, processing, computation, acceptable normal parameters, technique and reading should be known to conduct subjective assessments when EGG is used to resolve stomach dysfunction. Therefore appropriate application of non-invasive EGG should go on providing more information and insight in understanding these limitations. And so the aim of this study were to contribute the evolution of the EGG to enter the clinical world as a routine check-up method and to develop new time-frequency analysis method for the detection of gastric dysrhythmia from the EGG.

Transcutaneous electrical nerve stimulation (TENS) improves upper GI symptoms and balances the sympathovagal activity in scleroderma patients

To assess the impact of transcutaneous electrical nerve stimulation (TENS) at gastrointestinal (GI) acupoints on GI symptoms and quality of life in scleroderma patients, 17 patients filled out SF-36 and GI symptom questionnaires before the electrocardiogram was recorded for two intervals: baseline and TENS. At home, patients applied TENS for 14 days, then were reassessed. Acutely, TENS application significantly increased sympathetic and vagal activities vs. baseline (P=0.02 and P=0.004), respectively. Prolonged TENS application normalized the sympathovagal balance (P=0.04), decreased GI symptom scores (P=0.02) and increased the physical functioning score (SF36), which strongly correlated with the change in the sympathovagal balance (r=0.6, P=0.02). In conclusion, TENS at GI acupoints offers a potential option in the treatment of upper GI symptoms, but further study is necessary.

Electrogastrography: basic knowledge, recording, processing and its clinical applications

The slow wave (SW) of the gastrointestinal (GI) tract mainly functions to trigger the onset of spike to elicit smooth muscle contraction, which provides the essential power of motility. Smooth muscle myogenic control activity or SW is believed to originate in the interstitial cells of Cajal (ICC). The electrical coupling promotes interaction between muscle cells, and ICC additionally contribute to SW rhythmicity. Stomach SW originates in the proximal body showing the continuous rhythmic change in the membrane potential and propagates normally to the distal antrum with a regular rhythm of approximately 3 c.p.m. A technique using electrodes positioned on the abdominal skin to pick up stomach rhythmic SW refers to electrogastrography (EGG). The stomach SW amplitude is very weak, while many visceral organs also produce rhythmic electricities, for example heartbeat, respiration, other organs of the GI tract and even body movements. Thus noise other than SW should be filtered out during the recording, while motion artifacts are visually examined and deleted. Finally, the best signal among all recordings is selected to compute EGG parameters based on spectral analysis. The latter is done not only to tranform frequency domain to time domain but also to provide information of time variability in frequency. Obtained EGG parameters include dominant frequency/power, % normal rhythm, % bradygastria, % tachygastria, instability coefficient and power ratio. Clinical experience in EGG has been markedly accumulated since its rapid evolution. In contrast, lack of standardized methodology in terms of electrode positions, recording periods, test meals, analytic software and normal reference values makes the significance of EGG recording controversial. Unlike imaging or manometrical studies, stomach motility disorders are not diagnosed based only on abnormal EGG parameters. Limitations of EGG recording, processing, computation, acceptable normal parameters, technique and reading should be known to conduct subjective assessments when EGG is used to resolve stomach dysfunction. Understanding basic SW physiology, recording methodology and indications may open EGG as a new domain to approach the stomach motor dysfunction.

Stomach myoelectrical response of patients with gastroesophageal reflux disease receiving omeprazole treatment

BACKGROUND AND AIM

Proton pump inhibitor treatment is effective for gastroesophageal reflux disease (GERD). It is unknown whether these agents effect any change in the stomach myoelectricity of GERD patients. Electrogastrographic (EGG) recording was used to study the probable effect of omeprazole on GERD patients.

METHODS

Nineteen endoscopically confirmed GERD patients and 38 dyspepsia-free controls were invited to receive EGG recording. After daily omeprazole treatment for 4 weeks, the symptomatic response of GERD patients was scaled, healing of erosive esophagitis was endoscopically assessed, and EGG recording was repeated for comparison.

RESULTS

Before treatment, GERD patients and controls displayed similar dominant frequency, whereas the former had higher dominant power compared with controls, either in fasting (29.2 +/- 6.0 dB compared with 25.3 +/- 3.8 dB, P < 0.01) or postprandial (31.9 +/- 5.6 dB compared with 27.7 +/- 3.8 dB, P < 0.001) recording. They also had diminished percentile normal rhythm (2-4 c.p.m.), irrespective of fasting (40.2 +/- 14.5% compared with 65.8% +/- 23.5%, P < 0.001) or postprandial (47.5 +/- 23.3% compared with 77.9 +/- 16.8%, P < 0.001) recording. After omeprazole treatment, healing was achieved in 12 patients (63.2%). Among the abnormal EGG parameters, only the postprandial percentile normal rhythm was restored (47.5 +/- 23.3% compared with 65.2 +/- 20.8%, P < 0.01).

CONCLUSIONS

Gastroesophageal reflux disease patients may have obvious dysrhythmia and higher myoelectrical power. Effective omeprazole treatment only improves the postprandial myoelectrical regularity, whereas abnormal EGG parameters remain impaired.