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Effects of duodenal distension on gastric and intestinal myoelectrical activities
April 1998 motility. The system may be used from the pharynx to the GE junction, with either solid state or perfused MANO, with VF images, and with MANOVF, and provides an array of data visualization and parameter extraction software tools designed both for rapid diagnostics and for in-depth motility evaluations. The MDS has been extended to evaluate a variety of data including EMG, acoustic transducer, nasal canula, and tongue pressure, although the system is particularly well suited to high-resolution MANO (6-20 ports spaced 1.5 cm or less) where the isocontour representation of pressure is a valuable clinical tool and interpolated pressure along the catheter at fixed time can be correlated with VF images. A "Reports" module allows the user to choose an array of variables for automatic extraction, storage and printing. Results. The MDS software has been developed under the Windows 95 operating system and functions through an array of intuitive easy-to-use graphical interfaces, pull-down menus, buttons, sliders, and dialogue boxes. Multiple channel data may be interpolated onto the "space-time continuum" using a sophisticated interpolation scheme that minimizes spatial resolution required for accurate interpolation and maximizes isocontour quality. The same or multiple datasets may be viewed in different or within a single split windows simultaneously and in different formats, including standard "strip chart," line isocontour, color isocontour, or spatial. Temporal or spatial pressure distributions may be animated with or without VF to identify features otherwise missed with static images. Scales may be changed at will and subsets of data may be easily extracted for special examination. Within "Reports" three layers of information are recorded: "Single Swallow" data, "Multiple Swallow" data, and a "Research Report" which presents statistics from chosen multiple patient reports. The MDS can automatically separate a motility exam into single swallows and allows the clinician to easily adjust its choices. Once done the system can identify simultaneous contractions, high or low pressure amplitudes, durations, wave speed, etc. With an array of interactive tools the user can extract parameters from selected space-time points and easily align MANO and VF data. Application and Discussion. To date the MDS has been used in research on motility of the esophagus, pharynx, UES, and stomach. A preliminary clinical evaluation of the esophagus was carried out within The Johns Hopkins Swallowing Center and a formal clinical evaluation is planned in the near future. All indications are that the MDS has the potential to increase significantly the level and quality of data available from classical techniques and enhance evaluation, diagnostic and management of dysphagia. Supported by the National Institutes of Health, Grant R41 DK52058 • G3248 EFFECTS OF DUODENAL DISTENSION ON GASTRIC AND INTESTINAL MYOELECTRICAL ACTIVITIES. J. Liang, L. W. Qian, X. P. Zou, J.D.Z. Chen, Lynn Institute for Healthcare Research, Oklahoma City, Oklahoma. The aim of this study was to investigate the effect of duodenal distension on gastrointestinal myoelectrical activity. Methods: Six female hound dogs (17.5-19.5 kg) were involved in this study. They were implanted with 3 pairs of serosal electrodes in the proximal antrum, 4 pairs of serosal electrodes in the proximal jejunum, and a fistula 20 cm distal to the pylorus. Each study consisted of a recording of gastrointestinal myoelectrical activity for 30 rain in the fasting state and for 90 rain during duodenal balloon distension of 30 ml of air. Spectral analyses were performed to compute the power, the percentage of normal slow waves and the minute-by-minute variation of the gastric and intestinal slow waves. The ranges of the normal slow waves were 3.5-6.0 cpm for gastric recordings and 18-22 cpm for intestinal recordings. Results: 1) Intestinal slow waves were severely impaired by duodenal distension. The percentage of the 18-22 cpm waves was progressively reduced from 90.8 -+ 8.4% (mean -+ SD) at baseline to 73.8 -+ 10.2%, 57.2 -+ 11.4%, 53.7_+ 16.0%, during the 1st, 2nd and 3rd 30 rain of distension (p<0.05, ANOVA); The minute-by-minute variation (SD) of slow wave frequency was significantly increased from 1.55-+0.67 at baseline to 7.53-+2.21, 9.10 -+ 1.80, 9.11 -+ 2.88 cpm during the 1st, 2nd and 3rd 30 min of distension (p<0.03, ANOVA). The power of the slow wave was similarly decreased (p<0.05). 2) Gastric slow waves were not significantly affected by duodenal distension. The mean value of the percentage of the gastric slow waves were 84.0% -+ 15.4%, 78.1% + 27.1%, 82.3% -+ 15.5%, and 91.2% -+ 10.5% (p>0.2) during the baseline, 1st, 2nd, and 3rd 30 rain of distension respectively. The minute-by-minute SD of slow wave frequency was 0.40 -+0.20, 0.93 -+ 1.63, 0.70-+ 1.19, and 0.39 -+0.22 cpm (p>0.3) during the baseline, 1st, 2nd, and 3rd 30 min of distension respectively. Conclusion: Duodenal distension induces myoelectrical dysrhythmia in the small bowel, but not in the stomach. Duodenal distension may be used as a model of intestinal motor disorders. • G3249 INTESTINAL PACING INCREASES INTESTINAL CONTRACTILITY IN DOGS. J. Liang and J. D. Z. Chen, Lynn Institute for Healthcare Research, Oklahoma City, Oklahoma. The aim of this study was to develop a new method to quantitatively evaluate the contractility of intestinal myoelectrical activity and then to investigate the effect of intestinal pacing on the contractility of intestinal myoelectrical activity. Method: 1) Six female hound dogs (17.5-19.5 kg) implanted with 4 pairs of serosal electrodes in the proximal jejunum and a fistula 20 cm distal to the pylorus were studied. Each study consisted of a control session and a pacing session. In the control session, the recording of intestinal myoelectrical activity was made for 30 min in the fasting state (baseline) and for 90 min during duodenal balloon distension of 30 ml of air. The pacing session was the same as the control session except that intestinal pacing was performed
Motility and Nerve-Gut Interactions A789
during the 2nd 30-min of duodenal distension. The pacing signal was composed of periodic pulses with a width of 160ms, amplitude of 4mA and frequency of 20 cycles/min (cpm). 2) The power of spikes in the intestinal myoelectrical recordings was defined and calculated as follows. First, the signals were filtered using a bandpass filter (4-8Hz) to extract the spikes. This removed the slow waves and noise. Then, the power (dB) of the spikes (filtered signals) were calculated. Changes of the power with respect to the baseline were compared for the 1st, 2nd and 3rd 30-min of the 90-rain distension. Results: 1) Spike activity was effectively reflected by the power of spikes defined in this study. The power of spikes in Fig. 1 and Fig. 2 was 22.7 dB and 13.1 dB respectively. 2) Intestinal pacing increased the spike activity of intestinal myoelectrical signals. The power changes of spikes with respect to the baseline in the control session were -0.50 + 1.23, -0.0059 -+0.91 and 1.17-+0.85 dB (p>0.5, ANOVA) for the 1st, 2nd and 3rd 30 min of distension, while the power change during pacing (the 2nd 30 min of distension) was 16.4 -+3.0 dB (p<0,00001 in comparison with the 1st 30 rain of distension). The effect of pacing lasted after pacing during the 3rd 30 min of distension, and the power change was 3.5 _+1.2 dB (p<0.015 in comparison with the 1st 30 min of distension). The difference between the control and pacing session during the 2nd 30 min of distension was also significant (p<0.00001). Conclusion: The power of spikes can quantitatively evaluate the contractility of intestinal myoelectrical activity. Intestinal pacing is able to increase the contractility of intestinal myoelectrical activity.
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• G3250 DIAGNOSTIC IMPACT OF ELIMINATING EGG MOTION ARTIFACTS USING NEURAL NETWORKS. HC Lien, JC Fu*, CH Tsai*, CA Troy*. Talchung Veterans General Hospital, Da-Yeh University*, Taiwan, ROC. Background. The cutaneous electrogastrogram (EGG) is a potential useful tool for evaluating gastric motor disorders. However, the reliability of EGG interpretations is limited because of low signal-to-noise ratios resulting from inevitable motion artifact contamination. In this paper, we used Neural Networks (NN) to eliminate motion artifacts, and evaluate its effect on EGG reading. Methods. Sixteen healthy adults (10M/6F, aged 21-45), consumed a meal which consisted of 2 fried eggs, 2 slices of toast and 500 ml 5% glucose water (412 kcal). An EGG was recorded 30 minutes before and 60 minutes after the meal, with the patients in supine position as still as possible. The EGG was performed with a portable one-channel EGG recorder (Digitrapper EGG, Synetics Medical Inc., Irving, Texas) at a sampling rate of 4 Hz. The EGG data were digitized and processed by an in-house developed backpropagation NN to remove contamination caused by motion artifacts. The NN has 20 nodes in input layer and hidden layer and 2 nodes in output layer to indicate the status of the corresponding input segment (normal signal or motion artifact signal). Running spectral analysis was done via the fast Fourier transform (FFT) with 256-sec windows and a 64-see offset to achieve 75% overlap. Three features - dominant frequency (DF), dominant amplitude (DA) and area under curve (AUC) - were extracted from each spectrum. The 3 cycles per min (3CPM) was defined as dominant frequency ranged from 2.4 to 3.7 CPM. The definition of 3CPM% was the percentage of 3CPM in band-pass frequency ranged from 0 to 15 CPM. Data are expressed as mean + SEM and were analyzed using Student's t test. Results, Each case contains 25 spectra for preprandial period and 53 spectra for postprandial period. The percentages of motion artifacts removed contaminated FVT lines were 0 ~ 80% for preprandial period and 0 ~ 47% for postprandial period, respectively. DF did not change significantly (P>0.05) after removing the motion artifacts in both preprandial and postprandial periods in all 16 cases. (p>0.05) DA and AUC, during preprandial period, did not decrease significantly (p>0.05) after removing motion artifacts. During postprandial period, DA and AUC did not decrease significantly (p>0.05) when motion artifact is less than 20%. However, there were 7 cases whose motion artifacts were more than 20% in postprandial period, 3 in them showed significant decrease of DA and AUC (p<0.05). In addition, during postprandial period, there was negative correlation between percentage of motion artifacts removed and reduction of DA and AUC after removing motion artifacts (r = -0.62, p <0.05; r = -0.65, p <0.01). The 3CPM% change after removing motion artifacts were 3.0% -+ 6.0% for preprandial period and 0.8%-+ 2.9% for postprandial period, respectively. Although the average discrepancies of 3CPM% were not big, they had positive correlation with the percentage of motion artifact removed. (r = 0.65, p <0.01 for preprandial period, r =0.57, p<0.05 for postprandial period) Conclusions Our preliminary data suggest that DF was not changed by removal of motion artifacts. However, the extent of change in DA and AUC in postprandial period had negative correlation with the percentage of motion artifacts removed. The discrepancies of 3CPM% in both periods, though small in usual situation, also had positive correlation with the percentage of motion artifact removed. Funded by National Science Council, ROC, Grand No. NSC 87-2213-E-212007.
Motility and Nerve-Gut Interactions A789
during the 2nd 30-min of duodenal distension. The pacing signal was composed of periodic pulses with a width of 160ms, amplitude of 4mA and frequency of 20 cycles/min (cpm). 2) The power of spikes in the intestinal myoelectrical recordings was defined and calculated as follows. First, the signals were filtered using a bandpass filter (4-8Hz) to extract the spikes. This removed the slow waves and noise. Then, the power (dB) of the spikes (filtered signals) were calculated. Changes of the power with respect to the baseline were compared for the 1st, 2nd and 3rd 30-min of the 90-rain distension. Results: 1) Spike activity was effectively reflected by the power of spikes defined in this study. The power of spikes in Fig. 1 and Fig. 2 was 22.7 dB and 13.1 dB respectively. 2) Intestinal pacing increased the spike activity of intestinal myoelectrical signals. The power changes of spikes with respect to the baseline in the control session were -0.50 + 1.23, -0.0059 -+0.91 and 1.17-+0.85 dB (p>0.5, ANOVA) for the 1st, 2nd and 3rd 30 min of distension, while the power change during pacing (the 2nd 30 min of distension) was 16.4 -+3.0 dB (p<0,00001 in comparison with the 1st 30 rain of distension). The effect of pacing lasted after pacing during the 3rd 30 min of distension, and the power change was 3.5 _+1.2 dB (p<0.015 in comparison with the 1st 30 min of distension). The difference between the control and pacing session during the 2nd 30 min of distension was also significant (p<0.00001). Conclusion: The power of spikes can quantitatively evaluate the contractility of intestinal myoelectrical activity. Intestinal pacing is able to increase the contractility of intestinal myoelectrical activity.
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Fig.1.
. 0 275 280 285 495 Signal with spikes Fig.2.
500
505
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Signal without spikes
• G3250 DIAGNOSTIC IMPACT OF ELIMINATING EGG MOTION ARTIFACTS USING NEURAL NETWORKS. HC Lien, JC Fu*, CH Tsai*, CA Troy*. Talchung Veterans General Hospital, Da-Yeh University*, Taiwan, ROC. Background. The cutaneous electrogastrogram (EGG) is a potential useful tool for evaluating gastric motor disorders. However, the reliability of EGG interpretations is limited because of low signal-to-noise ratios resulting from inevitable motion artifact contamination. In this paper, we used Neural Networks (NN) to eliminate motion artifacts, and evaluate its effect on EGG reading. Methods. Sixteen healthy adults (10M/6F, aged 21-45), consumed a meal which consisted of 2 fried eggs, 2 slices of toast and 500 ml 5% glucose water (412 kcal). An EGG was recorded 30 minutes before and 60 minutes after the meal, with the patients in supine position as still as possible. The EGG was performed with a portable one-channel EGG recorder (Digitrapper EGG, Synetics Medical Inc., Irving, Texas) at a sampling rate of 4 Hz. The EGG data were digitized and processed by an in-house developed backpropagation NN to remove contamination caused by motion artifacts. The NN has 20 nodes in input layer and hidden layer and 2 nodes in output layer to indicate the status of the corresponding input segment (normal signal or motion artifact signal). Running spectral analysis was done via the fast Fourier transform (FFT) with 256-sec windows and a 64-see offset to achieve 75% overlap. Three features - dominant frequency (DF), dominant amplitude (DA) and area under curve (AUC) - were extracted from each spectrum. The 3 cycles per min (3CPM) was defined as dominant frequency ranged from 2.4 to 3.7 CPM. The definition of 3CPM% was the percentage of 3CPM in band-pass frequency ranged from 0 to 15 CPM. Data are expressed as mean + SEM and were analyzed using Student's t test. Results, Each case contains 25 spectra for preprandial period and 53 spectra for postprandial period. The percentages of motion artifacts removed contaminated FVT lines were 0 ~ 80% for preprandial period and 0 ~ 47% for postprandial period, respectively. DF did not change significantly (P>0.05) after removing the motion artifacts in both preprandial and postprandial periods in all 16 cases. (p>0.05) DA and AUC, during preprandial period, did not decrease significantly (p>0.05) after removing motion artifacts. During postprandial period, DA and AUC did not decrease significantly (p>0.05) when motion artifact is less than 20%. However, there were 7 cases whose motion artifacts were more than 20% in postprandial period, 3 in them showed significant decrease of DA and AUC (p<0.05). In addition, during postprandial period, there was negative correlation between percentage of motion artifacts removed and reduction of DA and AUC after removing motion artifacts (r = -0.62, p <0.05; r = -0.65, p <0.01). The 3CPM% change after removing motion artifacts were 3.0% -+ 6.0% for preprandial period and 0.8%-+ 2.9% for postprandial period, respectively. Although the average discrepancies of 3CPM% were not big, they had positive correlation with the percentage of motion artifact removed. (r = 0.65, p <0.01 for preprandial period, r =0.57, p<0.05 for postprandial period) Conclusions Our preliminary data suggest that DF was not changed by removal of motion artifacts. However, the extent of change in DA and AUC in postprandial period had negative correlation with the percentage of motion artifacts removed. The discrepancies of 3CPM% in both periods, though small in usual situation, also had positive correlation with the percentage of motion artifact removed. Funded by National Science Council, ROC, Grand No. NSC 87-2213-E-212007.