Gastrointestinal Myoelectric Measurements via Simultaneous External and Internal Electrodes in Pigs

INTRODUCTION

Currently, there is no accurate noninvasive measurement system to diagnose gastrointestinal (GI) motility disorders. Wireless skin patches have been introduced to provide an accurate noninvasive measurement of GI myoelectric activity which is essential for developing neuro-stimulation devices to treat GI motility disorders. The aim of this study is to compare the external and internal electrical signal measurements in ambulatory pigs.

METHODS

Yucatan pigs underwent placement of internal electrodes on the stomach, small intestine, and colon. Wires were brought through the abdominal wall. Signals were collected by a wireless receptor. Four external patches were placed on the abdominal skin to record the signals simultaneously. Pigs were kept for 6 d while the sensors were continuously recording the data from both systems.

RESULTS

Internal sensors detected rich signals from each organ. The stomach had a dominant frequency that ranged from 4 to 4.5 cpm, with occasional higher frequencies at 2, 3 and 4 times that. Small intestine signals had their primary energy in the 12-15 cpm range. Colon signals primarily displayed a dominant broad peak in the 4-6 cpm region. External skin patches detected a substantial fraction of the activities measured by the internal electrodes. A clear congruence in the frequency spectrum was observed between the internal and external readings.

CONCLUSIONS

Internally measured myoelectrical signals confirmed different patterns of rhythmic activity of the stomach, small intestine, and colon. Skin patches provided GI myoelectric measurement with a range of frequencies that could be useful in the diagnosis and treatment of motility disorders.

POS1251 INCIDENCE AND OUTCOMES OF SARS-CoV-2 INFECTION IN PATIENTS WITH SYSTEMIC AUTOIMMUNE RHEUMATIC DISEASES: A POPULATION-BASED STUDY OF MORE THAN FOUR MILLION INHABITANTS IN THE LAZIO ITALIAN REGION

Background

The impact of the severe acute respiratory syndrome Coronavirus 2 disease (COVID-19) pandemic on people with systemic autoimmune rheumatic diseases (SARDs) remains to be fully established. It is unclear whether SARDs are an independent risk factor for COVID-19 infection and poor outcome.

Objectives

The aim of our study is to assess the incidence and prognosis of test-proven SARS-CoV-2 infection during the first COVID-19 wave in a large population of SARD patients of the Lazio Italian region.

Methods

We retrospectively evaluated in a cohort of 4.716.119 subjects aged over 18 years and affiliated to the health system of the Lazio Italian Region, the incidence and 30-day outcomes of COVID-19 infection in 40.490 SARD pts and compared to the affiliated population as incidence rate ratio adjusted for demographics and comorbidities (adjIRR). SARD diagnosis and comorbidities were derived from medical administrative records using the Chronic Related Group classification system. Data on COVID-19 infection were derived from a dedicated regional digital network.

Results

The risk of COVID-19 infection was increased in patients with Psoriatic Arthritis (adjIRR=1.21, 95% CI 1.10-1.33) and Undifferentiated Connective Tissue Disease (adjIRR=1.26, 95% CI 1.03-1.54). The risk of hospitalisation was higher in patients with Axial Spondylarthritis (adjIRR=2.16, 95% CI 1.45-3.22), and Systemic Vasculitis (adjIRR=1.81, 95% CI 1.07-3.06) while the risk of Intensive care unit admission was higher in Systemic Erythematous Lupus (adjIRR=3.67, 95% CI 1.52-8.83) and primary Sjögren Syndrome (adjIRR=4.13, 95% CI 1.71-9.96) patients. An increased COVID-19 mortality was reported in patients with Rheumatoid Arthritis (adjIRR=1.50, 95% CI 1.04-2.17), Systemic Erythematous Lupus (adjIRR=2.67, 95% CI 1.10-6.44), primary Sjögren Syndrome (adjIRR=2.51, 95% CI 1.12-5.62), and Scleroderma (adjIRR=4.60, 95% CI 2.06-10.29).

Conclusion

The incidence of severe COVID-19 is not increased in the same percentage in SARDs. Each SARD presents a peculiar pattern in terms of increased risk of COVID-19 incidence, hospitalisation, intensive care unit admission and death, that is not linked to the immunosuppressive behaviour of the disease.

Disclosure of Interests

None declared

Pilot Validation of a New Wireless Patch System as an Ambulatory, Noninvasive Tool That Measures Gut Myoelectrical Signals: Physiologic and Disease Correlations

BACKGROUND AND AIMS

Limited means exist to assess gastrointestinal activity in a noninvasive, objective way that is highly predictive of underlying motility disorders. The aim of this paper is to demonstrate the feasibility of recording myoelectric gastrointestinal activity by cutaneous patches and to correlate myoelectric signals with gastrointestinal function in various clinical settings.

METHODS

A novel wireless patch system (WPS) (G-Tech Medical) that acquires gastrointestinal myoelectrical signals was placed on the patients' anterior abdomens. Data were transmitted wirelessly to a mobile device with a user interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters, and nominally assigned them to specific gastrointestinal organs based on their frequencies.

RESULTS

The inherent reproducibility of the WPS measurement technique itself and from the underlying gut activity, coupled with source validation and sensitivity to changes in gut activity in several physiologic and pathologic states, demonstrates its feasibility, safety, and performance in clinical settings.

CONCLUSIONS

The novel WPS technology, measuring myoelectric intestinal activity noninvasively and continuously over multiple days, is feasible in a wide range of clinical settings, highlighting its promise in the diagnosis and management of motility disorders. Further research is required for more extensive validation and to determine how best to employ this information to optimize patient care.

Cutaneous Patches to Monitor Myoelectric Activity of the Gastrointestinal Tract in Postoperative Pediatric Patients

PURPOSE

Limited means exist to assess gastrointestinal activity in pediatric patients postoperatively. Recently, myoelectric gastrointestinal activity recorded by cutaneous patches has been shown in adult patients to be predictive of clinical return of gastrointestinal function postoperatively. The aim of this case series is to demonstrate the feasibility of this system in pediatric patients and to correlate myoelectric signals with return of bowel function clinically.

METHODS

Pediatric patients undergoing abdominal surgery were recruited to have wireless patches placed on the abdomen within two hours postoperatively. Myoelectric data were transmitted wirelessly to a mobile device with a user-interface and forwarded to a cloud server where processing algorithms identified episodes of motor activity, quantified their parameters and nominally assigned them to specific gastrointestinal organs based on their frequencies.

RESULTS

Three patients (ages 5 months, 4 year, 16 year) were recruited for this study. Multiple patches were placed on the older subjects, while the youngest had a single patch due to space limitations. Rhythmic signals of the stomach, small intestine, and colon could be identified in all three subjects. Patients showed gradual increase in myoelectric intestinal and colonic activity leading up to the first recorded bowel movement.

CONCLUSION

Measuring myoelectric intestinal activity continuously using a wireless patch system is feasible in a wide age range of pediatric patients. The increase in activity over time correlated well with the patients' return of bowel function. More studies are planned to determine if this technology can predict return of bowel function or differentiate between physiologic ileus and pathologic conditions.

Monitoring gastric myoelectric activity after pancreaticoduodenectomy for diet "readiness"

Postoperative delayed gastric emptying (DGE) is a frustrating complication of pancreaticoduodenectomy (PD). We studied whether monitoring of postoperative gastric motor activity using a novel wireless patch system can identify patients at risk for DGE. Patients ( n = 81) were prospectively studied since 2016; 75 patients total were analyzed for this study. After PD, battery-operated wireless patches (G-Tech Medical) that acquire gastrointestinal myoelectrical signals are placed on the abdomen and transmit data by Bluetooth. Patients were divided into early and late groups by diet tolerance of 7 days [enhanced recovery after surgery (ERAS) goal]. Subgroup analysis was done of patients included after ERAS initiation. The early and late groups had 50 and 25 patients, respectively, with a length of stay (LOS) of 7 and 11 days ( P < 0.05). Nasogastric insertion was required in 44% of the late group. Tolerance of food was noted by 6 versus 9 days in the early versus late group ( P < 0.05) with higher cumulative gastric myoelectrical activity. Diminished gastric myoelectrical activity accurately identified delayed tolerance to regular diet in a logistical regression analysis [area under the curve (AUC): 0.81; 95% confidence interval (CI), 0.74-0.92]. The gastric myoelectrical activity also identified a delayed LOS status with an AUC of 0.75 (95% CI, 0.67-0.88). This stomach signal continued to be predictive in 90% of the ERAS cohort, despite earlier oral intake. Measurement of gastric activity after PD can distinguish patients with shorter or longer times to diet. This noninvasive technology provides data to identify patients at risk for DGE and may guide the timing of oral intake by gastric "readiness." NEW & NOTEWORTHY Limited clinical indicators exist after pancreaticoduodenectomy to allow prediction of delayed gastric emptying (DGE). This study introduces a novel, noninvasive, wireless patch system capable of accurately monitoring gastric myoelectric activity after surgery. This system can differentiate patients with longer or shorter times to a regular diet as well as provide objective data to identify patients at risk for DGE. This technology has the potential to individualize feeding regimens based on gastric activity patterns to improve outcomes.

Eye contact as an antecedent to compliant behavior

Many experimenters and practitioners regard eye contact between instructor and learner as a facilitator, if not a prerequisite, to the effective instruction of sighted people. Without scientifically supporting the practice of demanding eye contact, experimenters, nonetheless, advocate its use and offer a variety of procedures to promote its acquisition. To justify the widespread use of demanded eye contact and to explain its role functionally, one experiment and data from six replications with nine subjects are presented. The primary experiment provides an empirical base for the training of eye contact prior to instruction. In a multiple-baseline design across two students demanded eye contact resulted in levels of compliance that were double and triple those of baseline. A tentative functional analysis of demanded eye contact is presented, followed by a discussion of the relationship of eye contact to attending.

Modification of behavior problems in the home with a parent as observer and experimenter

Four parents enrolled in a Responsive Teaching class carried out experiments using procedures they had devised for alleviating their children's problem behaviors. The techniques used involved different types of reinforcement, extinction, and punishment. One parent increased the frequency of the wearing of an orthodontic device during five daily time checks by making an immediate monetary payoff contingent on wearing the device. A second parent increased the number of points earned for doing daily household tasks by providing back-ups for which the points could be exchanged. The parents of a 4-yr-old boy decreased the frequency of whines, cries, and complaints by removing social attention when such behavior occurred. A mother decreased the duration of time it took for her 5-yr-old daughter to get dressed by making permission to watch television contingent on dressing within 30 min of the time she got up in the morning. Brief reversals of contingencies were used to show causal relationships between the procedures used and the changes in behavior. Checks on the reliability of measurement were made by persons present in the home.

Calculated and measured brachytherapy dosimetry parameters in water for the Xoft Axxent X-Ray Source: An electronic brachytherapy sourcea)

A new x-ray source, the model S700 Axxent X-Ray Source (Source), has been developed by Xoft Inc. for electronic brachytherapy. Unlike brachytherapy sources containing radionuclides, this Source may be turned on and off at will and may be operated at variable currents and voltages to change the dose rate and penetration properties. The in-water dosimetry parameters for this electronic brachytherapy source have been determined from measurements and calculations at 40, 45, and 50 kV settings. Monte Carlo simulations of radiation transport utilized the MCNP5 code and the EPDL97-based mcplib04 cross-section library. Inter-tube consistency was assessed for 20 different Sources, measured with a PTW 34013 ionization chamber. As the Source is intended to be used for a maximum of ten treatment fractions, tube stability was also assessed. Photon spectra were measured using a high-purity germanium (HPGe) detector, and calculated using MCNP. Parameters used in the two-dimensional (2D) brachytherapy dosimetry formalism were determined. While the Source was characterized as a point due to the small anode size, < 1 mm, use of the one-dimensional (1D) brachytherapy dosimetry formalism is not recommended due to polar anisotropy. Consequently, 1D brachytherapy dosimetry parameters were not sought. Calculated point-source model radial dose functions at gP(5) were 0.20, 0.24, and 0.29 for the 40, 45, and 50 kV voltage settings, respectively. For 1<r<7 cm, measured point-source model radial dose functions were typically within 4% of calculated results. Calculated values for F(r, theta) for all operating voltages were within 15% of unity along the distal end (theta=0 degree), and ranged from F(1 cm, 160 degrees) = 0.2 to F(15 cm, 175 degrees) = 0.4 towards the catheter proximal end. For all three operating voltages using the PTW chamber, measured dependence of output as a function of azimuthal angle, psi, was typically on average +/-3% for 0 degree < or = psi < or = 360 degrees. Excluding an energy response function, measurements of normalized photon energy spectra were made for three operating voltages, and were typically within 2% agreement with the normalized Monte Carlo calculated spectra. In general, the model S700 Source exhibited depth dose behavior similar to low-energy photon-emitting low dose rate sources 125I and l03Pd, yet with capability for variable and much higher dose rates and subsequently adjustable penetration capabilities. This paper presents the calculated and measured in-water brachytherapy dosimetry parameters for the model S700 Source at the aforementioned three operating voltages.

A comparison of the effectiveness of brief versus traditional functional analyses

The study compared a brief and an extended (i.e., traditional) functional analyses with three adults with serious developmental disabilities. Two of the subjects exhibited high levels of aggressive behavior, whereas the third engaged in self-injury. Both analyses examined conditions such as tangible reinforcement, attention, demand, alone and play (i.e., baseline). The brief functional analysis also included functional communication training in which the subjects learned a relevant mand. The brief and extended functional analyses revealed the same controlling variables in all cases, but the brief functional analyses took less than 20% of the time in analog conditions as the extended analyses. These results further the case for the utility of brief functional analyses. We caution, however, that behavior analysts should not generalize from a study that involved only three subjects and that brief functional analyses may be particularly sensitive to establishing operations.

The impact of functional analysis methodology on treatment choice for self-injurious and aggressive behavior

Self-injurious behavior (SIB) and aggression have been the concern of researchers because of the serious impact these behaviors have on individuals' lives. Despite the plethora of research on the treatment of SIB and aggressive behavior, the reported findings have been inconsistent regarding the effectiveness of reinforcement-based versus punishment-based procedures. We conducted a literature review to determine whether a trend could be detected in researchers' selection of reinforcement-based procedures versus punishment-based procedures, particularly since the introduction of functional analysis to behavioral assessment. The data are consistent with predictions made in the past regarding the potential impact of functional analysis methodology. Specifically, the findings indicate that, once maintaining variables for problem behavior are identified, experimenters tend to choose reinforcement-based procedures rather than punishment-based procedures as treatment for both SIB and aggressive behavior. Results indicated an increased interest in studies on the treatment of SIB and aggressive behavior, particularly since 1988.

Matching training procedures to outcomes. A behavioral and quantitative analysis

To analyze the effects of matching the prompting procedure used in training to the specific behavior chain to be taught, 3 students with mild to moderate retardation were taught four independent tasks: making a bagged lunch, playing a matching game with a peer, ordering food at a restaurant, and participating in a social conversation. Following baseline, all 3 students were exposed to one of two types of training procedures for each task: a least-to-most prompting procedure or a most-to-least prompting procedure. The type of training procedure was counter-balanced across students and tasks, whereas performance on the tasks was evaluated within a combination of a multiple-baseline design across participants and multiple-probe design across tasks. When the method of prompting was matched to the naturally occurring discriminative stimulus (SD) of the training stimulus, it greatly affected acquisition and maintenance of the skill in terms of differences in levels of and variability of performance. The most-to-least method of prompting, the matched method in these cases, was more efficient and effective for acquisition and generalization of the bagged-lunch and matching-game skills. The least-to-most method, the matched method in these cases, was more efficient and effective for social questions and ordering-food skills.

Septal lesions impair rats' Morris test performance but facilitate left-right response differentiation

Lesions in the septum impaired performance on the Morris test, a task in which the rat locates a hidden escape platform by use of fixed landmarks, but facilitated a water maze-based left-right response differentiation, a task in which the rat finds a hidden escape ramp by means of its internal sense of direction. These results are interpreted as supporting an allocentric/egocentric dichotomy with respect to navigation, and support the notion that rats approach spatial problems with a hierarchy of potential solutions in which allocentric solutions take precedence over egocentric ones. The septal lesions are inferred to disrupt the allocentric mapping system.

Memory. When less is more

Loss of memory for the characteristics of stimuli (i.e., forgetting of stimulus attributes) can lead to increases in behavior, a consequence quite different from the impairments associated with the forgetting of responses. Evidence from animal and human research for the forgetting of stimuli as a distinct memory principle is presented, and the methodological and conceptual implications of this pervasive type of memory loss are considered. Malleability of eyewitness memory, cognitive confusions, sleeper and familiarity effects, and temporal distortions in inferences and attributions are among the varied behavioral phenomena that can be accounted for in terms of forgetting of stimulus attributes.

Evaluation of a new mechanical atherectomy system (TRAC) in normal canine coronary arteries. Transluminal Rotary Atherectomy System

BACKGROUND

The feasibility and safety of a new mechanical atherectomy device, the Transluminal Rotary Atherectomy System (TRAC), for coronary application was examined in vivo in eight dogs. The system operates over a standard balloon coronary guide wire and excises and removes the atherosclerotic material in a single application.

METHODS

The TRAC was introduced percutaneously using routine cardiac catheterization technique in four open-chest dogs (acute experiments) and in four closed-chest dogs (chronic experiments).

RESULTS

Coronary angiography at the end of the procedure and 1-3 days later demonstrated normal coronary arteries without evidence of dissection, perforation, spasm, or thrombus formation. Macroscopic examination revealed perivascular bleeding along the treated coronary arteries in two out of eight dogs. Microscopic examination of these arteries demonstrated minimal endothelial peeling. Histology of the other coronary arteries demonstrated normal intact blood vessels without evidence for thrombus formation.

CONCLUSIONS

These results demonstrate that it is feasible and relatively safe to introduce and operate the new TRAC mechanical atherectomy system in the normal coronary arteries of a beating dog heart.

Partial callosotomy and left-right response differentiation in the rat: Separate anterior and posterior facilitatory effects

Earlier research demonstrated that complete section of the corpus callosum in the rat reduced the number of trials required to acquire a left-right response differentiation (LRRD). This study was designed to investigate whether the facilitatory effect on LRRD could be produced by section of an anatomical subdivision of the callosum. Rats with sections of the anterior or posterior corpus callosum mastered the LRRD task faster than sham subjects, but more slowly than rats with total callosal section; section of the middle portion of the callosum had no such effect. The partial facilitatory effects of anterior and posterior callosotomy appear to be independent, and suggest that the callosal intermixing of lateral information, which contributes to left-right confusion, occurs at both the sensory and motor levels of processing.

Improved acquisition of left-right response differentiation in the rat following section of the corpus callosum

Split-brained rats learned a left-right response differentiation in a water maze significantly faster than rats with sham surgery. It is unlikely that this superiority resulted from improvement in performance variables since callosotomized rats did not differ significantly from sham operates in speed of acquisition of a brightness discrimination in the same apparatus. Additionally, callosotomy likewise had no effect on the acquisition of a water-maze task requiring consistent unilateral responses. The superiority of the callosotomized animals in forming the left-right response differentiation supports a hypothesis implicating the forebrain commissures in left-right confusion.

Bladder outlet obstruction versus impaired detrusor contractility: the role of outflow

The uroflow curves of 45 men with either bladder outlet obstruction or impaired detrusor contractility were retrospectively reviewed. The definitive diagnoses were attained by clinical and video-urodynamic studies with simultaneous detrusor pressure and uroflow measurements. Eight parameters were analyzed to determine if uroflow can differentiate obstruction from impaired contractility. There were no differences between the 2 groups in any of the parameters. This finding suggests that uroflowmetry as a single examination cannot distinguish between bladder outlet obstruction and impaired detrusor contractility.

Failure of induced asymmetries to improve left-right response differentiation in the rat

Rats (and humans) appear to be able to distinguish between left and right by referring to an intrinsic asymmetry as a navigational aid; this suggests that experimentally induced asymmetries might also facilitate such a distinction. We assessed the effects of asymmetries produced by unilateral shaving, unilateral vibrissotomy, and asymmetrical cortical lesions on acquisition of a left-right response differentiation. None of the treatments improved performance relative to appropriate control treatments; the rats were evidently unable to use these induced asymmetries to form the lateral differentiation. The results are related to evidence provided in an earlier report (Noonan & Axelrod, 1989) that even some reliable intrinsic asymmetries cannot function as navigational aids.