Multichannel Electrogastrography Research Articles

17 Multi‐channel electrogastrography (MEGG), gastric dysmotility and duodenal dysmotility in patients with functional dyspepsia: a self‐control study

Abnormalities in gastric slow waves and motility are frequently reported in functional dyspepsia patients. However, simultaneous assessment of the slow wave and motility abnormalities has rarely been done.The aim of this study is to assess gastric slow waves and antroduodenal motility simultaneous and determine the correlation among all measures in patients with functional dyspepsia.Methods: Thirty‐one patients (8 M, 23 F, mean age 48.7, Range (23–79) with functional dyspepsia were assessed for severity of upper gastrointestinal symptoms, the multi‐channel electrogastrogram (MEGG) and antroduodenal manometry. The MEGG and manometry were recorded for 3–4 hours in the fasting state and for two hours after a solid meal. Computerized spectral analysis methods were utilized to compute the following MEGG parameters in the fasting and fed state. Dominant frequency, Dominant power and % of 2–4 cycles min­1 slow waves. Common gastrointestinal symptoms of nausea, vomiting, upper abdominal pain, bloating, early satiety and etc. were assessed for symptom severity and graded.Results: (1) The MEGG was abnormal in 71.0% of patients. The abnormalities included normal slow waves lower than 70% in fasting state (51.6% of patients) and in fed state (48.4% of patients), a decrease in dominant power in 28.9% of patients. (2) Antral motility was abnormal in 83.9% and duodenal motility was abnormal in 74.2% of patients. There was a significant correlation between these two abnormalities. (3) For the MEGG and antral motility, 19 of 31 patients had both abnormal MEGG and abnormal antral motility; two of 31 patients had both normal MEGG and normal antral motility. For the MEGG and duodenal motility, these values were 16/31 and 2/31 respectively. (4) The patients showed high symptom scores particularly to upper abdominal pain, nausea and belch, with an average symptom score of 2.5/4 for pain, 2.5/4 for nausea and 2.3/4 for belch, respectively. The mean total score was 22/52 for all symptoms. (5) No significant correlation was noted between the symptom scores and any of the MEGG or motility parameters.Conclusions: More than two thirds of patients with functional dyspepsia have abnormalities in the MEGG and antral duodenal motility. The sensitivity of these two different methods is essentially the same. Abnormalities in gastric motility and duodenal motility are correlated whereas the symptoms are not correlated with any of the MEGG or motility parameters.

28 The alteration of multi‐channel Electrogastrography and autonomic nervous system function in patients with gastroesophageal reflux disease with test meal

The aims of this study were to utilize multi‐channel electrogastrography (MEGG) and power spectra analysis of Heart Rate Variability (HRV) to investigate the effects of test meal on MEGG and autonomic nervous system (ANS) function in patients with gastroesophageal reflux disease (GERD).Methods: Sixteen patients with the diagnosis of GERD were enrolled in this study (11 M, 5 F, mean age: 47 yrs) and 16 healthy subjects (HS) matched for age and gender were recruited as control (11 M, 5 F, mean age: 47 yrs). MEGG was recorded simultaneously with the electrocardiogram (ECG) recording for 30 min in the fasting state and 60 min after a standard test meal (450 Kcal). MEGG parameters included dominant frequency (DF), dominant power (DP), the normal percentage of 2–4 cpm gastric slow waves (%N) and the percentage of slow wave coupling (%SWC). ANS parameters included sympathovagal balance LF/HF Ratio, mainly sympathetic activity LF and vagal activity HF.Results: (1) Compared with fasting state, test meal significantly increased the DF but decreased the %N and %SWC in both GERD patients and HS in the 1st 30 min and 2nd 30 min fed state (P < 0.05). DP was not significantly altered by test meal in both groups in fed state. However, there is no significant difference between 1st 30 min and 2nd 30 min fed state for DF, %N and %SWC. 2) Compared with fasting state, test meal significantly increased the LF/HF ratio and LF but decreased the HF in both groups in the 1st 30 min after meal (P < 0.05), however, the increase of LF/HF ratio and LF but decrease of HF were still present in HS whereas absent in patients with GERD in the 2nd 30 min fed state. There is no significant difference between 1st 30 min and 2nd 30 min fed state for those ANS parameters. (3) There was no significant difference between GERD patients and HS in any of those MEGG and ANS parameters neither in fasting state nor in fed state. (4) There was no significant correlation between MEGG parameters and ANS parameters neither in fasting state nor in fed state in both groups.Conclusions: Both patients with GERD and HS may have similar response to test meal in MEGG test. GERD patients could not maintain the response to test meal longer in ANS test suggests that GERD patients may have impaired ANS regulation to test meal.

22 Comparison of multichannel electrogastrograms obtained with the use of three different electrode types

Background/Aims: Multichannel recording of the gastric myoelectrical activity (GMA) is a promising evolution of electrogastrography. In the study we searched for electrodes the most suitable to obtain high quality multi‐channel electrogastrograms.Methods: Twelve young volunteers (9 F, 3 M, aged 24.3 ± 0.6 years) underwent on separate days three four‐channel electrogastrographic recordings of the GMA: 30 min fasted and 90 min after a solid meal stimulation. The electrogastrograms were recorded in randomized order with 3M Red Dot class Ag/AgCl electrodes designed primarily for long‐term electrocardiographic monitoring: type­2222 (conductive area, CA/total area, TA): 2.00/10.24 cm2, type­2271 2.54/29.64 cm2, type­2660 11.64/11.64 cm2 (total surface conductive!) and subsequently analysed with Polygram Net™ EGG 311224 software (Medtronic, USA). Electrical resistance between active electrodes relative to the reference one was measured with a digital ohmmeter before and after the recording session.Results: Type­2660 yielded consistently higher electrical resistance than the other electrode types, moreover in the case of type­2271 and type­2660 electrical conductivity significantly improved at the end of the recording relative to the basal measurement. Analysis of variance involving the relative time‐share of normogastria, meal‐induced change in dominant power, as well as a set of parameters unique for the multichannel electrogastrography and intended to characterize the so‐called spatial displacement of the gastric slow waves did not reveal any statistically significant effect of the electrode type on the parameters of the multichannel electrogastrogram. Although, when particular numerical data were inspected, type­2271 was found to perform slightly worse than the other electrode types. Type­2271 was also rated the less handy among the electrodes tested.Conclusion: Multichannel surface electrogastrography seems to be technically feasible with any type of high quality Ag/AgCl electrodes available on the market, whereas small dimensions enabling easy placement on the abdomen may be a feature favouring the choice of a particular electrode type for this examination.

Centre-specific multichannel electrogastrographic testing utilizing wavelet-based decomposition

Although the principles of electrogastrography (EGG) have been known for years, the clinical utility of EGG has not been clearly demonstrated, and EGG recording and analysis techniques have not been fully standardized. The aim of this study was to develop a multichannel EGG technique for detecting abnormal gastric motility using an EGG database specifically designed for a particular testing centre, maximizing the sensitivity and the specificity of the test. Eight healthy volunteers formed a reference group to which 4 study groups (17 gastro-oesophageal reflux disease (GORD) patients, 7 functional dyspepsia patients, 8 post-fundoplication patients and 12 healthy volunteers) were compared. Eight-channel EGG was recorded in the postprandial and fasting states for 30 min each. The recorded signals were wavelet compressed and the resulting error (per cent root mean square difference (PRD)) after the compression was utilized to compare the study groups to the reference group. A threshold in the number of channels with significantly different PRD values was introduced. Sensitivity (SE), specificity (SP) and correct classification rate (CC) of the test in recognizing each clinical condition in the study groups for several channel thresholds and compressions were calculated, and were maximized. Increasing the compression and channel threshold levels improved the specificity, but decreased the sensitivity of the multichannel EGG test. An optimal combination region was identified based on a centre-specific adjustment of the channel threshold and the wavelet compression. The achieved maximum sensitivity, specificity and correct classification for this region in our test centre were as follows: GORD—SE 82.4%, SP 83.3%, CC 82.8%; functional dyspepsia—SE 100%, SP 75%, CC 84.2%; post-fundoplication—SE 75.0%, SP 83.3%, CC 80.0%. The utilization of a wavelet-based decomposition technique to process multichannel EGG signals can be a very effective method for enhancing the clinical utility of EGG, provided it is specifically developed for a given testing centre.

Correlation between gastric myoelectrical activity recorded by multi-channel electrogastrography and gastric emptying in patients with functional dyspepsia

Objective. To investigate the correlation between the parameters of multi-channel electrogastrography (MEGG) and gastric emptying in patients with functional dyspepsia. Material and methods. The MEGG study included 19 patients with functional dyspepsia and 19 healthy subjects. MEGG was recorded for 30 min in the fasting state and 60 min after a standard test meal (450 kcal). MEGG parameters included the power ratio (PR), the normal percentage of 2–4 cpm gastric slow waves (N%) and the percentage of slow wave coupling (%SWC). Gastric emptying was measured in the 19 patients by SPECT (single photon emission computerized tomography) and the gastric emptying parameters included lag phase (LP), half time of gastric emptying (T1/2), emptying rate of stable phase (ERSP), one hour retention rate (1HRR), and two hour retention rate (2HRR). Results. No significant difference in MEGG parameters was found between normal subjects and patients. There was a significant negative correlation between postprandial N% and LP (r= − 0.52, p<0.05) and a significant negative correlation between fasting %SWC and 1HRR (r= − 0.48, p<0.04) or 2HRR (r= − 0.48, p<0.05). Compared with the patients in the PR > 1 group, patients in the PR ≤ 1 group had significantly higher T1/2 and 2HRR but lower ERSP. Conclusions. Both the temporal regularity and spatial regularity of gastric slow waves have negative correlations with gastric emptying, which suggests that the impaired gastric myoelectrical activity may be responsible for the delayed gastric emptying in patients with functional dyspepsia.

Multichannel electrogastrography (EGG) in normal subjects: a multicenter study.

The aim of this study was to record gastric myoelectric activity using multichannel electrogastrography (EGG) and to determine if there are differences due to age, gender, body mass, and study location. In 61 normal subjects from four centers, fasting multichannel EGG was recorded for 1 h, followed by two 1-h postprandial recordings after a test meal. Variables assessed included dominant frequency (DF) and its power, percentage time in 2- to 4-cpm frequency, and percentage slow-wave coupling (%SWC). There were no significant differences in EGG parameters with respect to gender or age. Subjects with a BMI > 25 had a decrease in the absolute DF power but a similar increase in the postprandial DF power. Subjects with a BMI > 25 had a postprandial decrease in the %SWC compared to those with a BMI < 25. There was a decrease in postprandial %SWC in European/Asian centers compared to American centers. In conclusion, multichannel EGG provides assessment of electrical slow-wave coupling in addition to determining dominant frequency, power, and percentage normal rhythm. This multicenter study of normal subjects shows similar multichannel EGG values among different genders and ages. Body mass and ethnicity may impact on some of the EGG values.

Characterization of gastric myoelectrical rhythms in patients with systemic sclerosis using multichannel surface electrogastrography.

The aim of this study was to characterize multichannel surface electrogastrography (EGG) recordings in patients with systemic sclerosis (scleroderma, SSc) compared to normal controls. Ten SSc patients and 13 healthy age-matched controls were enrolled in this study. Gastric myoelectrical activity was recorded using a four-channel electrogastrograph with abdominal surface electrodes. The EGG was recorded in the morning for 1 hr in the fasting state, and 1 hr after a standardized (500 kcal) test meal. It was found that: (1) The regularity of the gastric slow wave was significantly lower in the SSc patients when compared with the normal controls in both fasting and fed states. (2) There was a significantly higher incidence of bradygastria in the SSc patients. (3) The SSc patients showed a significantly lower percentage of slow wave coupling among the four-channel EGGs than the controls. (4) In comparison with the controls, the patients showed an impaired spatial distribution of gastric slow wave power in both fasting and fed states and an impaired spatial distribution of slow wave frequency in the fasting state. It was concluded that SSc patients have an abnormal gastric slow wave as shown in the multichannel EGG as a decreased percentage of normal slow waves and impaired spatial coordination of gastric slow waves. The multichannel EGG may serve as a simple, noninvasive, and cost-effective method to assess gastric motility disorders and their relevance in patients with SSc.

Abnormal gastric slow waves in patients with functional dyspepsia assessed by multichannel electrogastrography.

The aim of this study was to utilize multichannel electrogastrography to investigate whether patients with functional dyspepsia had impaired propagation or coordination of gastric slow waves in the fasting state compared with healthy controls. The study was performed in 10 patients with functional dyspepsia and 11 healthy subjects. Gastric myoelectrical activity was measured by using surface electrogastrography with a specially designed four-channel device. The study was performed for 30 min or more in the fasting state. Special computer programs were developed for the computation of the propagation and coupling of the gastric slow wave. It was found that, compared with the healthy controls, the patients showed a significantly lower percentage of slow wave propagation (58.0 +/- 8.9 vs. 89.9 +/- 2.6%, P < 0.002) and a significantly lower percentage of slow wave coupling (46.9 +/- 4.4 vs. 61.5 +/- 6.9%, P < 0.04). In addition, the patients showed inconsistencies in the frequency and regularity of the gastric slow wave among the four-channel electrogastrograms (EGGs). It was concluded that patients with functional dyspepsia have impaired slow wave propagation and coupling. Multichannel EGG has more information than single-channel EGG for the detection of gastric myoelectrical abnormalities.

Usefulness of a developed four-channel EGG system with running spectrum analysis.

Electrogastrography (EGG) is a method of measuring action potentials on the abdomen. It is noninvasive, inexpensive and easy to measure. However, the EGG signal has a very low frequency (0.05 Hz) and an extremely low amplitude (10-100 microV). Consequently, its measured waveform is difficult to analyze and it is not yet completely understood. In this study, a four-channel EGG measurement system was built to measure the action potential of the stomach. This system was compared with the commercially available one-channel Digitrapper EGG. The 3 cpm percentages were compared between the best channel of the four-channel system and channel 1, whose electrode position was similar to the commercially available one-channel system for normal subjects. The average 3 cpm percentage of the best channel and channel 1 for preprandial measurement was 89.5% and 83.2%, respectively, and this was statistically significant (p < 0.001). Also the average 3 cpm percentage of the best channel and channel 1 for postprandial measurement was 90.4% and 76.5%, respectively, and this was statistically significant (p = 0.003). From these results, it can be concluded that a multi-channel EGG system is required for better EGG measurement.

Multichannel electrogastrography in children with neurological impairment

Multichannel electrogastrography in children with neurological impairment

Multichannel recording of human gastric electrical activity from the body surface

A method of simultaneous multichannel derivation and recording of gastric potentials from the surface of the anterior abdominal wall is described. By multichannel electrogastrography electrical activity can be recorded selectively in different parts of the stomach from the surface of the anterior abdominal wall. Spatiotemporal and correlation analysis of electrical activity of various parts of the stomach was carried out during digestion.