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Automated detection of gastric dysrhythmias from the electrogastrogram using artificial neural networks
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ABSTRACTS OF PAPERS
HYPERGLYCEMIA ALTERS AND BLUNTS RECI-OANAL CONTROLS: IMPLICATIONS
PERCEFl’ION OF RECTAL DISTENTION INHIBITORY REFLEXES IN NORMAL FOR DIABETIC CONSTIPATION.
qYD Cheq M Kim, W Hasler, C &yang. Dept of Int Med. Univ of Michigan, Ann Arbor, MI. The pathogenesis of constipation in diabetes mellitus is unclear. We have shown that hyperglycemia blunts gastrocolonic reflex and colonic peristaltic reflex contractions in normal volunteers, documenting inhibitory effects of elevated plasma glucose on efferent neural function. In this study, we tested if hyperglycemia alters rectal afferent neural function and local rectoanal reflex activity in 7 healthy volunteers using anotectal manometry, and if any inhibitory effects are due to hyperglycemia itself or to secondary hypcrinsulinemia. Subjects rated perception of graded rectal balloon inflation under control, hyperglycemic clamp, and euglycemic, hypcrinsulinemic clamp conditions. Hyperglycemic clamping to 255f 10 mg/dl increased volumes of inflation needed to elicit different levels of perception from basal values of 35*7 ml (threshold), 71fl3 ml (mild discomfort), 129+28 ml (moderate discomfort), 221f48 ml (severe discomfort), and 287&54 ml (maximal toler-ated pain) to 66&7 ml, 122*28 ml, 19lf45 ml, 252f57 ml, and 317f65 ml respectively. Differences were significant for all levels of perception except maximal tolerated pain (PcO.05). Rectal volume thresholds for detection of the rectoanal inhibitory reflex increased from lOzl2 ml under basal conditions to 28f6 ml with hyperglycemia (P
LES RELAXATION CHARACTERISTICS DETERMINED BY A SLEEVE SENSOR DURING CLINICAL MANOMETRY. GA Ereun and PJ Kahrilas. Dept of Medicine, Northwestern University Medical School, Chicago, IL. The sleeve sensor is commonly used to assess dynamic activity of the LES, yet no data exist describing LES function recorded by sleeve sensor during routine clinical manometries. We evaluated LES relaxation (LESR) characteristics observed in four well defined groups of patients. Methods: We retrospectively reviewed consecutive manometric recordings performed with consistent methodology over a 2 year period to identify patients with gastroesophageal reflux disease (GERD) (symptoms plus endoscopic esophagitis and/or positive Bernstein test), achalasia (compatible esophagram, endoscopy and subsequent effective treatment with dilation) and diffuse esophageal spasm (DES) (meeting criteria of Richter & Caste11 Ann Intern Med 1984;100:242). Patients wrth a normal EGD, negative Bernstein test and neither achalasia nor spasm served as patient controls. Manometric tracings (10 swallows each) were examined for basal LES pressure, residual pressure relative to distal sleeve site at maximal relaxation (Res LESP), duration of maximal relaxation (Relax Dur) and the interval from contraction onset in the proximal esophagus (15 cm above the sphincter) to the onset of LESR. Results: LES data for the 60 patient controls were as follows: residual LESP median= 1.8 mmHg, 95% confidence interval (CI) I-IOmmHg; relaxation duration median=2.2s, 95% CI 0.9-4.0s; interval from contraction onset to LESR mean=0.6s, 95%CI O1.7. The Table shows the number and percentages of patients in the disease grouts with values outside the 95% CI of the oatient controls. No significant differences in LESP timing were found. Res LESP>lO Relax Dur<0.9s Either GERD (n=63) 16 (25%) 2 (3%) 17 (27%) Achalasia (n=20) 13 (65%) 13 (65%) 16 (80%) DES (n=19) 1(5%) 6 (32%) 6 (32%) Conclusions: 1) Incomplete LES relaxation recorded bv a sleeve sensor (residual pressure> 1OmmHg) is a defining characteristic of achalasia but this finding is only 65% sensitive and 92% specific as an isolated observation. 2) If relaxation duration and residual pressure are both examined then these collective findings are 80% sensitive and 81% specific for achalasia.
GASTROENTEROLOGY Vol. 107, No. 4
AUTOMATED DETECTION OF GASTRIC DYSRHYTHMIAS FROM THE ELECTROGASTROGRAM USING ARTIFICIAL NEURAL NETWORKS. ZY Lin RW McCallum and JDZ Chen. Division of Gastroenteroiogy, Department of Medicine, University of Virginia, Charlottesville, VA Gastric dysrhythmias are associated with gastric motor disorders. The aim of this study was to automatically detect gastric dysrhythmias from the electrogastrogram (EGG) using the artificial neural network (NN) approach. Methods: EGG recordings were made for 30 min in the fasting state and 30 min after a 500 Kcal standardized meal in 20 patients with gastroparesis using an ambulatory EGG recorder (Synectics, Irving, TX). An artificial neural network (ANN) was developed for the classification of EGG data (normal or dysrhythmic). The ANN is a computational tool simulating the human brain nervous system. It contains input, output and hidden neurons, and interconnection weights between these neurons. It can be trained to capture the features of the presented data and perform classifications after sufficient training. In this study, the output of the network had two nodes, one standing for normal EGG and the other for dysrhythmic EGG. The EGG recording was divided into segments, each with 60 samples (1 min). The I-min EGG was defined as normal if the visual examination of its power spectrum indicated a clear frequency peak within 2.4 to 3.8 cycles/min. Otherwise it was defined as dysrhythmic. Results: Using the EGG data in 10 subjects as the training set and the EGG data in another 10 subjects as the testing set, it was found that the best type of input data to the network for this specific application was the modeling parameters of the EGG and the optimal network configuration was 22:15:2 (the number of input nodes: hidden nodes: output nodes). Using the optimized ANN, an accuracy of 95 % was achieved for the automated assessment of gastric dysrhythmias from the EGG. Conclusion: This study indicates that gastric dysrhythmias can be automatically detected from the EGG using the ANN approach.
BODY POSITION PROBABLY MODULATES ESOPHAGEAL MOTOR FUNCTIONS. FY Chang CT Lee, CL Yeh, SD Lee. Div. of Gastroenterology, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China. Esophageal manometry is usually performed in the supine position whereas human eating is rarely undergone in such position. Aim: To determine whether body position can influence esophageal manometric parameters. Methods: A low compliance pneumohydraulic infusion system was employed to measure esophageal motor functions. Twenty-six volunteers (M/F: 12/14, mean agefSE:34.0f2.0 yr) without any esophageal motor disturbance firstly underwent the mcasurcd esophageal manometry in the left decubitus position, then this procedure was repeated in the sitting position. The measurements included lower esophageal sphincter (LES) pressure and relax, dry swallow (DS) or wet swallow (WS) induced contractile amplitude and interval, and the peristaltic speed in lower esophagus. Results: Comparisons of the data obtained in both positions showed the following differences. Sitting evoked a higher LES pressure than that of left dccubitus (14.5fO.X mmHg vs. 12.M0.9 mmHg, p=O.Ol) whereas WS relax was more effective in left decubitus (99.tBzO.48 vs. 96.5+0.1%, p
ABSTRACTS OF PAPERS
HYPERGLYCEMIA ALTERS AND BLUNTS RECI-OANAL CONTROLS: IMPLICATIONS
PERCEFl’ION OF RECTAL DISTENTION INHIBITORY REFLEXES IN NORMAL FOR DIABETIC CONSTIPATION.
qYD Cheq M Kim, W Hasler, C &yang. Dept of Int Med. Univ of Michigan, Ann Arbor, MI. The pathogenesis of constipation in diabetes mellitus is unclear. We have shown that hyperglycemia blunts gastrocolonic reflex and colonic peristaltic reflex contractions in normal volunteers, documenting inhibitory effects of elevated plasma glucose on efferent neural function. In this study, we tested if hyperglycemia alters rectal afferent neural function and local rectoanal reflex activity in 7 healthy volunteers using anotectal manometry, and if any inhibitory effects are due to hyperglycemia itself or to secondary hypcrinsulinemia. Subjects rated perception of graded rectal balloon inflation under control, hyperglycemic clamp, and euglycemic, hypcrinsulinemic clamp conditions. Hyperglycemic clamping to 255f 10 mg/dl increased volumes of inflation needed to elicit different levels of perception from basal values of 35*7 ml (threshold), 71fl3 ml (mild discomfort), 129+28 ml (moderate discomfort), 221f48 ml (severe discomfort), and 287&54 ml (maximal toler-ated pain) to 66&7 ml, 122*28 ml, 19lf45 ml, 252f57 ml, and 317f65 ml respectively. Differences were significant for all levels of perception except maximal tolerated pain (PcO.05). Rectal volume thresholds for detection of the rectoanal inhibitory reflex increased from lOzl2 ml under basal conditions to 28f6 ml with hyperglycemia (P
LES RELAXATION CHARACTERISTICS DETERMINED BY A SLEEVE SENSOR DURING CLINICAL MANOMETRY. GA Ereun and PJ Kahrilas. Dept of Medicine, Northwestern University Medical School, Chicago, IL. The sleeve sensor is commonly used to assess dynamic activity of the LES, yet no data exist describing LES function recorded by sleeve sensor during routine clinical manometries. We evaluated LES relaxation (LESR) characteristics observed in four well defined groups of patients. Methods: We retrospectively reviewed consecutive manometric recordings performed with consistent methodology over a 2 year period to identify patients with gastroesophageal reflux disease (GERD) (symptoms plus endoscopic esophagitis and/or positive Bernstein test), achalasia (compatible esophagram, endoscopy and subsequent effective treatment with dilation) and diffuse esophageal spasm (DES) (meeting criteria of Richter & Caste11 Ann Intern Med 1984;100:242). Patients wrth a normal EGD, negative Bernstein test and neither achalasia nor spasm served as patient controls. Manometric tracings (10 swallows each) were examined for basal LES pressure, residual pressure relative to distal sleeve site at maximal relaxation (Res LESP), duration of maximal relaxation (Relax Dur) and the interval from contraction onset in the proximal esophagus (15 cm above the sphincter) to the onset of LESR. Results: LES data for the 60 patient controls were as follows: residual LESP median= 1.8 mmHg, 95% confidence interval (CI) I-IOmmHg; relaxation duration median=2.2s, 95% CI 0.9-4.0s; interval from contraction onset to LESR mean=0.6s, 95%CI O1.7. The Table shows the number and percentages of patients in the disease grouts with values outside the 95% CI of the oatient controls. No significant differences in LESP timing were found. Res LESP>lO Relax Dur<0.9s Either GERD (n=63) 16 (25%) 2 (3%) 17 (27%) Achalasia (n=20) 13 (65%) 13 (65%) 16 (80%) DES (n=19) 1(5%) 6 (32%) 6 (32%) Conclusions: 1) Incomplete LES relaxation recorded bv a sleeve sensor (residual pressure> 1OmmHg) is a defining characteristic of achalasia but this finding is only 65% sensitive and 92% specific as an isolated observation. 2) If relaxation duration and residual pressure are both examined then these collective findings are 80% sensitive and 81% specific for achalasia.
GASTROENTEROLOGY Vol. 107, No. 4
AUTOMATED DETECTION OF GASTRIC DYSRHYTHMIAS FROM THE ELECTROGASTROGRAM USING ARTIFICIAL NEURAL NETWORKS. ZY Lin RW McCallum and JDZ Chen. Division of Gastroenteroiogy, Department of Medicine, University of Virginia, Charlottesville, VA Gastric dysrhythmias are associated with gastric motor disorders. The aim of this study was to automatically detect gastric dysrhythmias from the electrogastrogram (EGG) using the artificial neural network (NN) approach. Methods: EGG recordings were made for 30 min in the fasting state and 30 min after a 500 Kcal standardized meal in 20 patients with gastroparesis using an ambulatory EGG recorder (Synectics, Irving, TX). An artificial neural network (ANN) was developed for the classification of EGG data (normal or dysrhythmic). The ANN is a computational tool simulating the human brain nervous system. It contains input, output and hidden neurons, and interconnection weights between these neurons. It can be trained to capture the features of the presented data and perform classifications after sufficient training. In this study, the output of the network had two nodes, one standing for normal EGG and the other for dysrhythmic EGG. The EGG recording was divided into segments, each with 60 samples (1 min). The I-min EGG was defined as normal if the visual examination of its power spectrum indicated a clear frequency peak within 2.4 to 3.8 cycles/min. Otherwise it was defined as dysrhythmic. Results: Using the EGG data in 10 subjects as the training set and the EGG data in another 10 subjects as the testing set, it was found that the best type of input data to the network for this specific application was the modeling parameters of the EGG and the optimal network configuration was 22:15:2 (the number of input nodes: hidden nodes: output nodes). Using the optimized ANN, an accuracy of 95 % was achieved for the automated assessment of gastric dysrhythmias from the EGG. Conclusion: This study indicates that gastric dysrhythmias can be automatically detected from the EGG using the ANN approach.
BODY POSITION PROBABLY MODULATES ESOPHAGEAL MOTOR FUNCTIONS. FY Chang CT Lee, CL Yeh, SD Lee. Div. of Gastroenterology, Veterans General Hospital-Taipei, Taipei, Taiwan, Republic of China. Esophageal manometry is usually performed in the supine position whereas human eating is rarely undergone in such position. Aim: To determine whether body position can influence esophageal manometric parameters. Methods: A low compliance pneumohydraulic infusion system was employed to measure esophageal motor functions. Twenty-six volunteers (M/F: 12/14, mean agefSE:34.0f2.0 yr) without any esophageal motor disturbance firstly underwent the mcasurcd esophageal manometry in the left decubitus position, then this procedure was repeated in the sitting position. The measurements included lower esophageal sphincter (LES) pressure and relax, dry swallow (DS) or wet swallow (WS) induced contractile amplitude and interval, and the peristaltic speed in lower esophagus. Results: Comparisons of the data obtained in both positions showed the following differences. Sitting evoked a higher LES pressure than that of left dccubitus (14.5fO.X mmHg vs. 12.M0.9 mmHg, p=O.Ol) whereas WS relax was more effective in left decubitus (99.tBzO.48 vs. 96.5+0.1%, p