Electrogastrographic norms in children: toward the development of standard methods, reproducible results, and reliable normative data

Tachygastria in Preterm Infants: A Longitudinal Cohort Study

OBJECTIVES

Tachygastria is a gastric dysrhythmia (>4 to ≤9 cycles per minute, cpm) associated with gastric hypomotility and gastrointestinal disorders. Healthy preterm infants spend more time in tachygastria than adults; however, normative values are not defined. We sought to determine the percent of time preterm infants spend in tachygastria.

METHODS

We conducted a longitudinal, prospective cohort study with weekly electrogastrography (EGG) recordings in 51 preterm <34 weeks' gestation and 5 term (reference) infants. We calculated percentage recording time in tachygastria (% tachygastria) and determined the mean ± standard deviation (SD) across EGG sessions. Mixed effects model was performed to test weekly variance in % tachygastria and gestational age effect. Successive pre- and post-prandial measurements were obtained to assess reproducibility of % tachygastria. We compared time to achieve full feeds between subjects with % tachygastria within 1 SD from the mean versus % tachygastria >1 SD from mean.

RESULTS

Three hundred seventy-six EGG sessions were completed (N = 56). Mean % tachygastria was 40% with SD ±5%. We demonstrated no change in % tachygastria across 9 postnatal weeks (P = 0.70) and no gestational age effect. No difference was demonstrated between successive pre- (P = 0.91) and post-prandial (P = 0.96) % tachygastria. Infants with 35%-45% tachygastria (within 1 SD from mean) had higher gestational age and less time to achieve full feeds than infants with <35% or >45% tachygastria.

CONCLUSIONS

EGG is a reproducible tool to assess % tachygastria in preterm infants. Clinical significance of increased or decreased % tachygastria needs further investigation to validate if 35%-45% tachygastria is safe for feeding.

Review of paediatric gastrointestinal physiology relevant to the absorption of orally administered medicines

Despite much progress in regulations to improve paediatric drug development, there remains a significant need to develop better medications for children. For the design of oral dosage forms, a detailed understanding of the specific gastrointestinal (GI) conditions in children of different age categories and how they differ from GI conditions in adults is essential. Several review articles have been published addressing the ontogeny of GI characteristics, including luminal conditions in the GI tract of children. However, the data reported in most of these reviews are of limited quality because (1) information was cited from very old publications and sometimes low quality sources, (2) data gaps in the original data were filled with textbook knowledge, (3) data obtained on healthy and sick children were mixed, (4) average data obtained on groups of patients were mixed with data obtained on individual patients, and (5) results obtained using investigative techniques that may have altered the outcome of the respective studies were considered. Consequently, many of these reviews draw conclusions that may be incorrect. The aim of the present review was to provide a comprehensive and updated overview of the available original data on the ontogeny of GI luminal conditions relevant to oral drug absorption in the paediatric population. To this end, the PubMed and Web of Science metadatabases were searched for appropriate studies that examined age-related conditions in the oral cavity, esophagus, stomach, small intestine, and colon. Maturation was observed for several GI parameters, and corresponding data sets were identified for each paediatric age group. However, it also became clear that the ontogeny of several GI traits in the paediatric population is not yet known. The review article provides a robust and valuable data set for the development of paediatric in vitro and in silico biopharmaceutical tools to support the development of age-appropriate dosage forms. In addition, it provides important information on existing data gaps and should provide impetus for further systematic and well-designed in vivo studies on GI physiology in children of specific age groups in order to close existing knowledge gaps and to sustainably improve oral drug therapy in children.

Anatomical variations of the stomach effects on electrogastrography

Routine screening and accurate diagnosis of chronic gastrointestinal motility disorders represents a significant problem in current clinical practice. Electrogastrography (EGG) provides a non-invasive option for assessing gastric slow waves, as a means of diagnosing gastric dysrhythmias. However, its uptake in motility practice has been limited partly due to an incomplete description of how the underlying gastric slow waves directly relate to EGG. This study aims to quantify the effects of various anatomical orientations of the stomach on EGG using a multiscale model of whole-organ slow wave activation and EGG. The orientation of the stomach was perturbed over six parameters: x, y, z translations and rotations. The perturbed simulations were compared to the original simulated model using root-mean-squared (RMS) errors and correlation coefficients. Simulations demonstrated that the perturbations had minimal influence on EGG, however channels located within close proximity of the stomach source were subject to large variation as a result of the perturbations. The results indicate that outside a critical area the effects of translation/rotation have minimal influence on the EGG, and thus beyond this critical area findings should be relatively comparable across patient groups. These findings show promise in advancing rational development of improved EGG methods towards a normative methodology and the formation of a normative database.

Continuous wavelet analysis of postprandial EGGs suggests sustained gastric slow waves may be slow to develop in infants with colic

BACKGROUND

Electrogastrography in conjunction with Fast Fourier transform has limited success in detecting low grade abnormalities in gastric electrophysiological activity owing to the non-stationarity of the signal. Analysis by continuous wavelet transform is suitable for non-stationary signals and was used to analyse EGG activity in babies with and without colic.

METHODS

Thirty minute postprandial EGG recordings were obtained from 23 sleeping breast-fed infants with clinically validated recurrent colic and 26 breast-fed non-colicky infants. Continuous wavelet transform analysis (CWT) identified three principal frequency components. The mean, standard deviation, and the number of frequency maxima that fell below one standard deviation from the mean were determined for each infant and each frequency.

KEY RESULTS

Three component frequencies in the ranges 1.4-2.5 cpm, 2.5-4.0 cpm, and 4.0-15 cpm were found in all EGGs. Pairwise comparisons of the characteristics of each of the frequency ranges by univariate analyses showed significant differences between colicky and non-colicky subjects only in the number of maxima in the mid range of frequencies that lay below one standard deviation from the mean. However, CWT based on all frequencies allowed discrimination of the EGGS of colicky from non-colicky babies on a basis of number of frequency maxima below one standard deviation from the mean in the midrange of frequencies and in the mean and standard deviation in the low range of frequencies that was likely a harmonic of the midrange.

CONCLUSIONS & INFERENCES

CWT allowed distinction of EGG signals from colicky and healthy babies. The results indicate that colic may result from tardiness in the establishment of coherent propagation of the gastric slow wave in colicky babies.

A Theoretical Analysis of Electrogastrography (EGG) Signatures Associated With Gastric Dysrhythmias

Routine screening and accurate diagnosis of chronic gastrointestinal motility disorders represent a significant problem in current clinical practice. The electrogastrography (EGG) provides a noninvasive option for assessing gastric slow waves, as a means of diagnosing gastric dysrhythmias, but its uptake in motility practice has been limited partly due to an incomplete sensitivity and specificity. This paper presents the development of a human whole-organ gastric model to enable virtual (in silico) testing of gastric electrophysiological dispersion in order to improve the diagnostic accuracy of EGG. The model was developed to simulate normal gastric slow wave conduction as well as three types of dysrhythmias identified in recent high-resolution gastric mapping studies: conduction block, re-entry, and ectopic pacemaking. The stomach simulations were then applied in a torso model to identify predicted EGG signatures of normal and dysrhythmic slow wave profiles. The resulting EGG data were compared using percentage differences and correlation coefficients. Virtual EGG channels that demonstrated a percentage difference over 100% and a correlation coefficient less than ±0.2 (threshold relaxed to ±0.5 for the ectopic pacemaker case) were further investigated for their specific distinguishing features. In particular, anatomical locations from the epigastric region and specific channel configurations were identified that could be used to clinically diagnose the three classes of human gastric dysrhythmia. These locations and channels predicted by simulations present a promising methodology for improving the clinical reliability and applications of EGG.

Gastric Dysmotility in Critically Ill Children: Pathophysiology, Diagnosis, and Management

OBJECTIVE

We aimed to review gastric dysmotility in critically ill children: 1) its pathophysiology, with a focus on critical care diseases and therapies that affect gastric motility, 2) diagnostic methodologies, and 3) current and future potential therapies.

DATA SOURCES

Eligible studies were identified from PubMed and MEDLINE.

STUDY SELECTION

Literature search included the following key terms: "gastric emptying," "gastric motility/dysmotility," "gastrointestinal motility/dysmotility," "nutrition intolerance," and "gastric residual volume."

DATA EXTRACTION

Studies since 1995 were extracted and reviewed for inclusion by the authors related to the physiology, pathophysiology, diagnostic methodologies, and available therapies for gastric emptying.

DATA SYNTHESIS

Delayed gastric emptying, a common presentation of gastric dysmotility, is present in up to 50% of critically ill children. It is associated with the potential for aspiration, ventilator-associated pneumonia, and inadequate delivery of enteral nutrition and may affect the efficacy of enteral medications, all of which may be result in poor patient outcomes. Gastric motility is affected by critical illness and its associated therapies. Currently available diagnostic tools to identify gastric emptying at the bedside have not been systematically studied and applied in this cohort. Gastric residual volume measurement, used as an indirect marker of delayed gastric emptying in PICUs around the world, may be inaccurate.

CONCLUSIONS

Gastric dysmotility is common in critically ill children and impacts patient safety and outcomes. However, it is poorly understood, inadequately defined, and current therapies are limited and based on scant evidence. Understanding gastric motility and developing accurate bedside measures and novel therapies for gastric emptying are highly desirable and need to be further investigated.

A theoretical analysis of the electrogastrogram (EGG)

In this study, a boundary element model was developed to investigate the relationship between the gastric electrical activity, also known as slow waves, and the electrogastrogram (EGG). A dipole was calculated to represent the equivalent net activity of gastric slow waves. The dipole was then placed in an anatomically-realistic torso model to simulate EGG. The torso model was constructed from a laser-scanned geometry of an adult male torso phantom with 190 electrode sites equally distributed around the torso so that simulated EGG could be directly compared between the physical model and the mathematical model. The results were analyzed using the Fast Fourier Transforms (FFT), spatial distribution of EGG potential and a resultant EGG based on a 3-lead configuration. The FFT results showed both the dipole and EGG contained identical dominant frequency component of 3 cycles per minute (cpm), with this result matching known physiological phenomenon. The -3 dB point of the EGG was 110 mm from the region directly above the dipole source. Finally, the results indicated that electrode coupling could theoretically be used in a similar fashion to ECG coupling to gain greater understanding of how EGG correlate to gastric slow waves.

Relationship among nausea, anxiety, and orthostatic symptoms in pediatric patients with chronic unexplained nausea

This study evaluated the relationship among nausea, anxiety, and orthostatic symptoms in pediatric patients with chronic unexplained nausea. We enrolled 48 patients (36 females) aged 15 ± 2 years. Patients completed the Nausea Profile, State-Trait Anxiety Inventory for Children and underwent 70° head upright tilt testing (HUT) to assess for orthostatic intolerance (OI) and measure heart rate variability (HRV). We found nausea to be significantly associated with trait anxiety, including total nausea score (r = 0.71, p < 0.01) and 3 subscales: somatic (r = 0.64, p < 0.01), gastrointestinal (r = 0.48, p = 0.01), and emotional (r = 0.74, p < 0.01). Nausea was positively associated with state anxiety, total nausea (r = 0.55, p < 0.01), somatic (r = 0.48, p < .01), gastrointestinal (r = .30, p < .05), and emotional (r = .64, p < .01) subscales. Within 10 min of HUT, 27 patients tested normal and 21 demonstrated OI. After 45 min of HUT, only 13 patients (27%) remained normal. Nausea reported on the Nausea Profile before HUT was associated with OI measured at 10 min of tilt (nausea total r = 0.35, p < 0.05; nausea emotional subscale r = 0.40, p < 0.01) and lower HRV at 10 min of HUT (F = 6.39, p = 0.01). We conclude that nausea is associated with both anxiety symptoms and OI. The finding of decreased HRV suggests an underlying problem in autonomic nervous system function in children and adolescents with chronic unexplained nausea.

Effect of fludrocortisone acetate on chronic unexplained nausea and abdominal pain in children with orthostatic intolerance

BACKGROUND

We hypothesized that orthostatic intolerance (OI) is associated with gastric dysrhythmias, nausea, and abdominal pain, which improves using fludrocortisone to treat OI.

METHODS

Patients (n=16, girls) with OI completed questionnaires before and after fludrocortisone treatment (age 14.8 ± 2.8 years). Ten patients underwent electrogastrograms (EGGs) before fludrocortisone.

RESULTS

All EGGs showed gastric dysrhythmias. Fludrocortisone reduced mean scores as follows: nausea, 3.1 ± 0.8 to 2.1 ± 1.1 (P=0.016); dizziness, 3.0 ± 1.0 to 2.2 ± 1.1 (P=0.0371); abdominal pain, 2.8 ± 1.3 to 1.9 ± 1.4 (P=0.0063); flushing, 2.3 ± 1.2 to 1.5 ± 1.4 (P=0.0476); and missing school, 2.2 ± 1.5 to 1.2 ± 1.5 (P=0.0078).

CONCLUSIONS

Chronic nausea and abdominal pain accompany OI and improve with OI treatment.

Electrogastrography abnormalities appear early in children with diabetes type 1

OBJECTIVE

The objective of the study was to evaluate gastric myoelectrical activity in young patients with diabetes and to correlate it with their metabolic control [fasting blood glucose, glycosylated haemoglobin, and fructosamine] and BMI during a 3 years follow-up.

METHODS

Surface electrogastrography (EGG) was performed on 49 children with diabetes aged 10.3±4.4 (mean±SD) years and 17 age-matched healthy controls after fasting glucose, glycosylated haemoglobin, and fructosamine were measured. EGG parameters [percentage of bradygastria, 3 cycles per minute, tachygastria, dominant frequency instability coefficient, and power ratio] were analysed and compared with blood analysis.

RESULTS

Patients with diabetes exhibited an increase in preprandial bradygastria 7.9±8.8 cpm (mean±SD) compared with controls 2.1±1.0 (P=0.011), with an associated decrease in preprandial normogastria (72.2±14.5 vs. 82.7±14.7; P=0.013). Normogastric power ratio (postprandial/ preprandial power) was significantly increased in the children with diabetes compared with controls (mean: 6.67 vs. 3.14, P=0.034). A longer duration of diabetes was associated with an increased risk of EGG abnormalities (P=0.036). Marked hyperglycaemia at the time of study was associated with postprandial bradygastria (P=0.01) and power ratio bradygastria (P=0.042). Changes in glycosylated haemoglobin, fructosamine and BMI did not affect EGG parameters.

CONCLUSIONS

EGG abnormalities, presented early in a high proportion of diabetic children, are related to the acute hyperglycaemia. These abnormalities are not consistently present in the follow-up studies and not related to the glycosylated haemoglobin and fructosamine. Diabetic autonomic neuropathy is therefore an unlikely pathogenic factor for EGG abnormalities in children with diabetes.

Gastric myoelectrical and motor abnormalities in children and adolescents with functional recurrent abdominal pain

BACKGROUND AND AIMS

Recurrent abdominal pain is common among children and adolescents. The majority of the affected patients have no apparent cause for their symptoms. This study evaluated gastric myoelectrical activity and motility abnormalities in children and adolescents with functional recurrent abdominal pain.

METHODS

Forty-two children with functional recurrent abdominal pain [19 (45.2%) males, mean 8 years, SD 3 years, 19 functional abdominal pain, 9 irritable bowel syndrome, 9 functional dyspepsia, 1 abdominal migraine, 1 aerophagia and 3 non-specific abdominal pain according to Rome III criteria] and 20 healthy children [10 (50%) males, mean 9 years, SD 2.7 years] from the same geographical area underwent electrogastrography (EGG), and ultrasonographic assessment of gastric emptying rate and antral motility.

RESULTS

Average gastric emptying rate, amplitude of antral contractions and antral motility index were lower in patients (46.5%, 74.3% and 6.5 respectively) compared to controls (66.17%, 89% and 8.3 respectively) (P < 0.001). Gastric emptying rate had a negative correlation with scores obtained for severity of symptoms (r = -0.63, P < 0.0001). Postprandial dominant frequency instability co-efficient (post-DFIC) was higher in patients than in controls (27.83% vs 18.3%, P = 0.0087), and correlated with the symptom score (r = 0.26, P = 0.045).

CONCLUSIONS

Gastric emptying and antral motility were significantly impaired in patients, indicating a possible role for gastric motility disturbances in the pathogenesis of childhood functional recurrent abdominal pain. Further studies, including therapeutic trials, are needed to confirm this association and for recommendation of prokinetic drugs in its management.

Post-infectious gastroparesis: clinical and electerogastrographic aspects

AIMS

Post-infectious gastroparesis (PIGP) is a subgroup of idiopathic gastroparesis. The aim of this study was to identify post-viral gastroparesis and to characterize clinical and electrogastrographic aspects of the disease and their usefulness as a diagnostic tool.

METHODS

Patients diagnosed with gastroparesis were defined as PIGP if they had a clear history of an acute viral illness prior to the development of their symptoms. All patients underwent evaluation of gastric emptying and electrogastrography (EGG).

RESULTS

Seven patients met the criteria for diagnosis of PIGP. Patients' age ranged from 3 months to 47 years. A specific virus was identified in two patients (one cytomegalovirus [CMV] and one Epstein-Barr virus [EBV]). EGG was pathological in six out of seven patients. In four out of seven patients, symptoms resolved spontaneously within 4 weeks to 12 months, three patients had improved but were still symptomatic at the time of the writing of this work.

CONCLUSION

We conclude that post-infectious gastroparesis is an uncommon and often over looked condition. It is self-limiting in most cases. EGG is pathological in most patients.

Autonomic nervous system response to a solid meal and water loading in healthy children: its relation to gastric myoelectrical activity

The aim of this study was to investigate the correlation of gastric myoelectrical and autonomic activities in healthy children. Simultaneous recordings of electrogastrography (EGG) and electrocardiogram (ECG) were performed in healthy children before and after a solid meal and water loading respectively. The autonomic activity was assessed by spectral analysis of the heart rate variability (HRV). The solid meal resulted in an increase in EGG-dominant frequency (2.92 cpm vs 3.16 cpm, P < 0.05), dominant power (46.9 dB vs 53.7 dB, P < 0.05) and percentage normal slow waves (81.9%vs 89.0%, P < 0.05), while only dominant power increased following water loading. Power in the low-frequency band of HRV (LF) was significantly increased and power in the high-frequency band of HRV (HF) significantly decreased following the solid meal. Postprandial LF was positively and HF negatively correlated with the postprandial increase in EGG-dominant power. Water loading was not associated with any significant changes in HRV parameters. These results suggest that both vagal and sympathetic pathways are involved in modulation of gastric myoelectrical activity.

An evaluation of adult electrogastrography criteria in healthy children

The current study examined whether electrogastrogram (EGG) recordings obtained from healthy children would be considered normal by standards established for adults and whether EGG patterns differ between children/adolescents and adults. Twenty-eight healthy children (54% females; ages 8-17 years; mean = 12.4 years) were evaluated and compared to 15 healthy adults evaluated previously. EGGs were recorded for 30 min in the fasting state and for 1 hr following a standard meal. For both pediatric and adult participants, there was a significant increase in both the dominant frequency and the dominant power from the pre- to the postprandial period (P < 0.001 for each). Using adult standards, the percentage normal slow waves was > 70% of the recording time in 96% of children in the fasting state and in 100% in the postprandial period. A postprandial power increase was seen in 89% of the children. In conclusion, our data indicate that American Motility Society (AMS) consensus adult criteria for a normal EGG are appropriate to apply to children and adolescents when utilizing methodology and meal challenge similar to those used to establish the adult norms.

Electrogastrography in pediatric functional dyspepsia: relationship to gastric emptying and symptom severity

OBJECTIVES

The aims of this study were to determine the electrogastrographic patterns in children with functional dyspepsia and to investigate the correlations among electrogastrogram (EGG), gastric emptying (GE), and pain severity.

METHODS

We studied 30 children (19 F; mean age 11.4 years) with functional dyspepsia. Electrogastrography was performed for 30 minutes fasting and for 1 hour during a GE test after ingestion of an isotope-labeled solid meal. The percent emptying was measured every 10 minutes for 1 hour after the meal. The dominant frequency of the EGG, the change in the postprandial peak power (deltaP), and percent dysrhythmia during each recording session were calculated. Specific symptoms were graded from 0 (none) to 4 (severe) by the patient.

RESULTS

Of 30 patients, 14 (47%) had slow GE, and 15 (50%) had abnormal EGG (dysrhythmia > or = 30% or deltaP < 0). GE was slow in 73% of patients with an abnormal EGG but was slow in only 20% of patients with normal EGG (P = 0.009). GE was negatively correlated with fasting bradygastria (r = -0.383, P = 0.04). Abdominal pain was the most severe dyspeptic symptom, both during fasting and after the meal. Patients with an abnormal EGG had an increased mean pain severity score (3.5 +/- 0.2 vs. 2.5 +/- 0.2, P = 0.002).

CONCLUSIONS

Sixty percent of functional dyspepsia subjects had either slow GE or abnormal EGG. Patients with abnormal EGG were more likely to have slow GE. EGG abnormalities were associated with more severe postprandial pain and should be considered a possible mechanism for dyspeptic symptoms.

Chronic gastritis is not associated with gastric dysrhythmia or delayed solid emptying in children with dyspepsia

To determine if chronic gastritis (CG) is associated with gastric dysrhythmia or delayed solid emptying in children with dyspepsia, 22 patients (7-15 years of age) with dyspepsia and normal gross endoscopies were studied. Antral biopsies were evaluated for chronic gastritis, and immunohistology was performed to determine densities of CD3+, CD20+, CD25+, and tryptase-positive cells. Electrogastrography (EGG) and gastric scintiscan evaluation were performed within 2-7 days of endoscopy. CG and increased immune cell densities were not associated with altered gastric emptying. Mean CD3+ cell counts were positively correlated with the percentage normal slow waves, and patients with a normal EGG had increased CD3+ cell density. In children with dyspepsia, chronic antral inflammation in the setting of a normal gross endoscopy is not associated with EGG abnormalities or delayed solid emptying. Chronic gastritis and gastric dysrhythmia may simply be two separate and distinct mechanisms resulting in the clinical entity of dyspepsia.

Inhibitory effects of stress on postprandial gastric myoelectrical activity and vagal tone in healthy subjects

The aim was to investigate gastric myoelectrical activity (GMA) and vagal activity in response to stress. The study was performed in 10 healthy subjects in three sessions (control, relaxation and stress). The control session was composed of 30-min recordings before and 30-min recordings after a test meal. The protocol of two other sessions was similar except that the fasting recording was extended to 60 min and the subjects were continuously watching a horror movie (stress) or guided meditation tape (relaxation) after the 30-min baseline. GMA was recorded using electrogastrography and heart rate variability (HRV) was derived from the electrocardiogram. Meal resulted in a postprandial increase in the dominant frequency (2.91 cpm vs 3.17 cpm, P < 0.007), dominant power (30.0 dB vs 32.5 dB, P < 0.05), and percentage of normal slow waves (79.8%vs 87.4%, P = 0.09). Similar responses were found in the relaxation session. Stress inhibited all these normal postprandial response and reduced the regularity of gastric slow waves (82.0%vs 66.0%, P < 0.01). In addition, spectral analysis of the HRV demonstrated an inhibition of postprandial vagal activity and an increase of postprandial sympathetic activity with stress. Stress has an inhibitory effect on postprandial GMA and this may involve both vagal and sympathetic pathway.

Use of electrogastrography in children

Electrogastrography (EGG), the measurement of gastric pacemeaker activity by means of surface electrodes, provides a noninvasive technique to detect and quantify the characteristics of the gastric slow wave. With a predominant frequency of three cycles per minute, the activity of the specialized cells responsible for this pacing, the interstitial cells of Cajal, is crucial in providing the underlying electrophysiologic changes that enable coordinated smooth muscle contraction and synchronized peristalsis. Advances in electronics and software to define frequency distribution, stability of the signal, postprandial changes, and other parameters have contributed to more widespread interest in EGG and its application to the investigation of functional gastrointestinal disturbances. Definition of pediatric norms and postnatal changes in the EGG of premature infants has provided the foundation for further studies investigating correlative changes with such important functions as gastric emptying and motility. The EGG remains a promising diagnostic tool. Future studies will help define its usefulness in identifying abnormal functions of the interstitial cells of Cajal.