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Kuruppu S, Cheng LK, Angeli-Gordon TR, Avci R, Paskaranandavadivel N. Electromechanical Response of Mesenteric Ischemia Defined Through Simultaneous High-Resolution Bioelectrical and Video Mapping. Ann Biomed Eng 2024; 52:588-599. [PMID: 37962674 DOI: 10.1007/s10439-023-03404-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 10/31/2023] [Indexed: 11/15/2023]
Abstract
Intestinal motility is governed in part by bioelectrical slow-waves and spike-bursts. Mesenteric ischemia is a substantial clinical challenge, but its electrophysiological and contractile mechanisms are not well understood. Simultaneous high-resolution bioelectrical and video mapping techniques were used to capture the changes in slow-waves, spike-bursts, and contractile activity during baseline, ischemia, and reperfusion periods. Experiments were performed on anesthetized pigs where intestinal contractions were quantified using surface strain and diameter measurements, while slow-wave and spike-bursts were quantified using frequency and amplitude. Slow-waves entrainment within the ischemic region diminished during ischemia, resulting in irregular slow-wave activity and a reduction in the frequency from 12.4 ± 3.0 cycles-per-minute (cpm) to 2.5 ± 2.7 cpm (p = 0.0006). At the end of the reperfusion period, normal slow-wave entrainment was observed at a frequency of 11.5 ± 2.9 cpm. There was an increase in spike-burst activity between the baseline and ischemia periods (1.1 ± 1.4 cpm to 8.7 ± 3.3 cpm, p = 0.0003) along with a spasm of circumferential contractions. At the end of the reperfusion period, the frequency of spike-bursts decreased to 2.7 ± 1.4 cpm, and contractions subsided. The intestine underwent tonal contraction during ischemia, with the diameter decreasing from 29.3 ± 2.6 mm to 21.2 ± 6.2 mm (p = 0.0020). At the end of the reperfusion period, the intestinal diameter increased to 27.3 ± 3.9 mm. The decrease in slow-wave activity, increase in spike-bursts, and tonal contractions can objectively identify ischemic segments in the intestine. It is anticipated that the use of electrophysiological slow-wave and spike-burst biomarkers, along with contractile measures, could identify mesenteric ischemia in surgical settings and allow an objective biomarker for successful revascularization.
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Affiliation(s)
- Sachira Kuruppu
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
- Riddet Institute, Centre of Research Excellence, Palmerston North, New Zealand
| | - Timothy R Angeli-Gordon
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
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Kuruppu S, Cheng LK, Avci R, Angeli-Gordon TR, Paskaranandavadivel N. Relationship Between Intestinal Slow-waves, Spike-bursts, and Motility, as Defined Through High-resolution Electrical and Video Mapping. J Neurogastroenterol Motil 2022; 28:664-677. [PMID: 36250373 PMCID: PMC9577564 DOI: 10.5056/jnm21183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/01/2022] [Accepted: 12/17/2022] [Indexed: 11/20/2022] Open
Abstract
Background/Aims High-resolution extracellular mapping has improved our understanding of bioelectric slow-wave and spike-burst activity in the small intestine. The spatiotemporal correlation of electrophysiology and motility patterns is of critical interest to intestinal function but remains incompletely defined. Methods Intestinal jejunum segments from in vivo pigs and rabbits were exteriorized, and simultaneous high-resolution extracellular recordings and video recordings were performed. Contractions were quantified with strain fields, and the frequencies and velocities of motility patterns were calculated. The amplitudes, frequencies, and velocities of slow-wave propagation patterns and spike-bursts were quantified and visualized. In addition, the duration, size and energy of spike-burst patches were quantified. Results Slow-wave associated spike-bursts activated periodically at 10.8 ± 4.0 cycles per minute (cpm) in pigs and 10.2 ± 3.2 cpm in rabbits, while independent spike-bursts activated at a frequency of 3.2 ± 1.8 cpm. Independent spike-bursts had higher amplitude and longer duration than slow-wave associated spike-bursts (1.4 ± 0.8 mV vs 0.1 ± 0.1 mV, P < 0.001; 1.8 ± 1.4 seconds vs 0.8 ± 0.3 seconds, P < 0.001 in pigs). Spike-bursts that activated as longitudinal or circumferential patches were associated with contractions in the respective directions. Spontaneous peristaltic contractions were elicited by independent spike-bursts and travelled slower than slow-wave velocity (3.7 ± 0.5 mm/sec vs 10.1 ± 4.7 mm/sec, P = 0.007). Cyclic peristaltic contractions were driven by slow-wave associated spike-bursts and were coupled to slow-wave velocity and frequency in rabbit (14.2 ± 2.3 mm/sec vs 11.5 ± 4.6 mm/sec, P = 0.162; 11.0 ± 0.6 cpm vs 10.8 ± 0.6 cpm, P = 0.970). Conclusions Motility patterns were dictated by patterns of spike-burst patches. When spike-bursts were coupled to slow-waves, periodic motility patterns were observed, while when spike-bursts were not coupled to slow-waves, spontaneous aperiodic motility patterns were captured.
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Affiliation(s)
- Sachira Kuruppu
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, New Zealand
- Riddet Institute, Center of Research Excellence, New Zealand
- Department of Surgery, Vanderbilt University, Nashville, USA
| | - Recep Avci
- Auckland Bioengineering Institute, University of Auckland, New Zealand
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Lin AY, Varghese C, Du P, Wells CI, Paskaranandavadivel N, Gharibans AA, Erickson JC, Bissett IP, O'Grady G. Intraoperative serosal extracellular mapping of the human distal colon: a feasibility study. Biomed Eng Online 2021; 20:105. [PMID: 34656127 PMCID: PMC8520224 DOI: 10.1186/s12938-021-00944-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/05/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Cyclic motor patterns (CMP) are the predominant motor pattern in the distal colon, and are important in both health and disease. Their origin, mechanism and relation to bioelectrical slow-waves remain incompletely understood. During abdominal surgery, an increase in the CMP occurs in the distal colon. This study aimed to evaluate the feasibility of detecting propagating slow waves and spike waves in the distal human colon through intraoperative, high-resolution (HR), serosal electrical mapping. METHODS HR electrical recordings were obtained from the distal colon using validated flexible PCB arrays (6 × 16 electrodes; 4 mm inter-electrode spacing; 2.4 cm2, 0.3 mm diameter) for up to 15 min. Passive unipolar signals were obtained and analysed. RESULTS Eleven patients (33-71 years; 6 females) undergoing colorectal surgery under general anaesthesia (4 with epidurals) were recruited. After artefact removal and comprehensive manual and automated analytics, events consistent with regular propagating activity between 2 and 6 cpm were not identified in any patient. Intermittent clusters of spike-like activities lasting 10-180 s with frequencies of each cluster ranging between 24 and 42 cpm, and an average amplitude of 0.54 ± 0.37 mV were recorded. CONCLUSIONS Intraoperative colonic serosal mapping in humans is feasible, but unlike in the stomach and small bowel, revealed no regular propagating electrical activity. Although sporadic, synchronous spike-wave events were identifiable. Alternative techniques are required to characterise the mechanisms underlying the hyperactive CMP observed in the intra- and post-operative period. NEW FINDINGS The aim of this study was to assess the feasibility of detecting propagating electrical activity that may correlate to the cyclic motor pattern in the distal human colon through intraoperative, high-resolution, serosal electrical mapping. High-resolution electrical mapping of the human colon revealed no regular propagating activity, but does reveal sporadic spike-wave events. These findings indicate that further research into appropriate techniques is required to identify the mechanism of hyperactive cyclic motor pattern observed in the intra- and post-operative period in humans.
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Affiliation(s)
- Anthony Y Lin
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
| | - Chris Varghese
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Cameron I Wells
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand
| | | | - Armen A Gharibans
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand.,Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Jonathan C Erickson
- Department of Physics-Engineering, Washington & Lee University, Lexington, VA, USA
| | - Ian P Bissett
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand.,Department of Surgery, Auckland City Hospital, Auckland, New Zealand
| | - Greg O'Grady
- Department of Surgery, Faculty of Medical and Health Sciences, University of Auckland, Private Bag 92019, 1142, Auckland, New Zealand. .,Department of Surgery, Auckland City Hospital, Auckland, New Zealand.
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Kuruppu S, Cheng LK, Angeli TR, Avci R, Paskaranandavadivel N. A Framework for Spatiotemporal Analysis of Gastrointestinal Spike Burst Propagation. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:4619-4622. [PMID: 31946893 DOI: 10.1109/embc.2019.8856924] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Gastrointestinal spike bursts are a bioelectrical phenomenon associated with motility. These events when initiated propagate a small distance and abruptly terminate activating a small area defined as a patch. Understanding normal and abnormal propagation patterns of these events may shed light on the root causes of functional motility disorders. This study develops an automated framework for spatiotemporal analysis of spike bursts. High-resolution electrical signals were obtained from the pig intestine, after which intestinal spike bursts were identified and clustered into their propagating wavefronts. Propagation velocity was estimated by fitting a polynomial surface to the activation times. The fit was able to estimate the velocity of spike burst patches covering at least six channels with an average RMSE of 0.4 s. Propagation within patches was visualized by plotting the fit as activation maps and velocity maps. Average velocities were calculated to compare the propagation characteristics of different types of patches. In the future, this framework will be extended to generate amplitude maps and spike burst duration maps. These tools can be used to analyze spike patch propagation and their relationship to motility.
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Zherebtsov AV, Tropskaya NS. Real-Time Recording and Processing of Spike Electrical Activity of the Small Intestine in Experiments on Rats. Bull Exp Biol Med 2020; 168:406-409. [PMID: 31938915 DOI: 10.1007/s10517-020-04719-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Indexed: 11/24/2022]
Abstract
Real-time recording technique and mathematical processing of the spike electrical activity in the small intestine were developed for chronic experiments on rats. Open-source software was employed to digitize electromyograms and to process them in a real-time mode with a fourth-order nonlinear differential energy operator. This method improved identification of spike electrical activity in the small intestine in experiments.
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Affiliation(s)
- A V Zherebtsov
- N. V. Sklifosovsky Research Institute of Emergency Medicine, Moscow Department of Health Care, Moscow, Russia.
| | - N S Tropskaya
- N. V. Sklifosovsky Research Institute of Emergency Medicine, Moscow Department of Health Care, Moscow, Russia
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Cherian Abraham A, Cheng LK, Angeli TR, Alighaleh S, Paskaranandavadivel N. Dynamic slow-wave interactions in the rabbit small intestine defined using high-resolution mapping. Neurogastroenterol Motil 2019; 31:e13670. [PMID: 31250520 DOI: 10.1111/nmo.13670] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 06/09/2019] [Accepted: 06/18/2019] [Indexed: 02/08/2023]
Abstract
BACKGROUND The motility in the small intestine is governed in part by myogenic bio-electrical events, known as slow waves. High-resolution multi-electrode mapping has improved our understanding of slow-wave propagation in the small intestine but has been applied in a limited number of in vivo animal studies. This study applied high-resolution mapping to investigate slow waves in the rabbit small intestine. METHODS A high-resolution flexible printed circuit board array (256 electrodes; 4 mm spacing) was applied in vivo to the rabbit intestine. Extracellular slow-wave activity was acquired sequentially along the length of the intestine. KEY RESULTS AND CONCLUSIONS The majority of the slow waves propagated in the antegrade direction (56%) while retrograde patterns were primarily observed in the distal intestine (29%). Colliding slow-wave events were observed across the length of the small intestine (15%). The interaction of competing pacemakers was mapped in spatiotemporal detail. The frequency and velocity of the slow waves were highest in the duodenum compared to ileum (20.0 ± 1.2 cpm vs 10.5 ± 0.9 cpm, P < 0.001; 14.4 ± 3.4 mm/s vs 12.3 ± 3.4 mm/s; P < 0.05). INFERENCES In summary, extracellular serosal slow-wave activity was quantified spatiotemporally along the length of the rabbit intestine. In particular, the study provides evidence toward the presence and interaction of slow-wave pacemakers acting along the small intestine and how they may contribute to the slow-wave frequency gradient along the length of the intestine.
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Affiliation(s)
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Surgery, Vanderbilt University, Nashville, Tennessee, USA.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Timothy R Angeli
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Saeed Alighaleh
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Riddet Institute Centre of Research Excellence, Palmerston North, New Zealand
| | - Niranchan Paskaranandavadivel
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand.,Department of Surgery, University of Auckland, Auckland, New Zealand
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O'Grady G, Angeli TR, Paskaranandavadivel N, Erickson JC, Wells CI, Gharibans AA, Cheng LK, Du P. Methods for High-Resolution Electrical Mapping in the Gastrointestinal Tract. IEEE Rev Biomed Eng 2018; 12:287-302. [PMID: 30176605 DOI: 10.1109/rbme.2018.2867555] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the last two decades, high-resolution (HR) mapping has emerged as a powerful technique to study normal and abnormal bioelectrical events in the gastrointestinal (GI) tract. This technique, adapted from cardiology, involves the use of dense arrays of electrodes to track bioelectrical sequences in fine spatiotemporal detail. HR mapping has now been applied in many significant GI experimental studies informing and clarifying both normal physiology and arrhythmic behaviors in disease states. This review provides a comprehensive and critical analysis of current methodologies for HR electrical mapping in the GI tract, including extracellular measurement principles, electrode design and mapping devices, signal processing and visualization techniques, and translational research strategies. The scope of the review encompasses the broad application of GI HR methods from in vitro tissue studies to in vivo experimental studies, including in humans. Controversies and future directions for GI mapping methodologies are addressed, including emerging opportunities to better inform diagnostics and care in patients with functional gut disorders of diverse etiologies.
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Erickson JC, Hayes JA, Bustamante M, Joshi R, Rwagaju A, Paskaranandavadivel N, Angeli TR. Intsy: a low-cost, open-source, wireless multi-channel bioamplifier system. Physiol Meas 2018; 39:035008. [PMID: 29406314 DOI: 10.1088/1361-6579/aaad51] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Multi-channel electrical recordings of physiologically generated signals are common to a wide range of biomedical fields. The aim of this work was to develop, validate, and demonstrate the practical utility of a high-quality, low-cost 32/64-channel bioamplifier system with real-time wireless data streaming capability. APPROACH The new 'Intsy' system integrates three main off-the-shelf hardware components: (1) Intan RHD2132 bioamplifier; (2) Teensy 3.2 microcontroller; and (3) RN-42 Bluetooth 2.1 module with a custom LabView interface for real-time data streaming and visualization. Practical utility was validated by measuring serosal gastric slow waves and surface EMG on the forearm with various contraction force levels. Quantitative comparisons were made to a gold-standard commercial system (Biosemi ActiveTwo). MAIN RESULTS Intsy signal quality was quantitatively comparable to that of the ActiveTwo. Recorded slow wave signals had high SNR (24 ± 2.7 dB) and wavefront propagation was accurately mapped. EMG spike bursts were characterized by high SNR (⩾10 dB) and activation timing was readily identified. Stable data streaming rates achieved were 3.5 kS s-1 for wireless and 64 kS s-1 for USB-wired transmission. SIGNIFICANCE Intsy has the highest channel count of any existing open-source, wireless-enabled module. The flexibility, portability and low cost ($1300 for the 32-channel version, or $2500 for 64 channels) of this new hardware module reduce the entry barrier for a range of electrophysiological experiments, as are typical in the gastrointestinal (EGG), cardiac (ECG), neural (EEG), and neuromuscular (EMG) domains.
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Affiliation(s)
- Jonathan C Erickson
- Department of Physics and Engineering, Washington and Lee University, Lexington, VA 24450, United States of America
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Mayne TP, Paskaranandavadivel N, Erickson JC, OGrady G, Cheng LK, Angeli TR. Improved Visualization of Gastrointestinal Slow Wave Propagation Using a Novel Wavefront-Orientation Interpolation Technique. IEEE Trans Biomed Eng 2018; 65:319-326. [PMID: 29364117 PMCID: PMC5902405 DOI: 10.1109/tbme.2017.2764945] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE High-resolution mapping of gastrointestinal (GI) slow waves is a valuable technique for research and clinical applications. Interpretation of high-resolution GI mapping data relies on animations of slow wave propagation, but current methods remain as rudimentary, pixelated electrode activation animations. This study aimed to develop improved methods of visualizing high-resolution slow wave recordings that increases ease of interpretation. METHODS The novel method of "wavefront-orientation" interpolation was created to account for the planar movement of the slow wave wavefront, negate any need for distance calculations, remain robust in atypical wavefronts (i.e., dysrhythmias), and produce an appropriate interpolation boundary. The wavefront-orientation method determines the orthogonal wavefront direction and calculates interpolated values as the mean slow wave activation-time (AT) of the pair of linearly adjacent electrodes along that direction. Stairstep upsampling increased smoothness and clarity. RESULTS Animation accuracy of 17 human high-resolution slow wave recordings (64-256 electrodes) was verified by visual comparison to the prior method showing a clear improvement in wave smoothness that enabled more accurate interpretation of propagation, as confirmed by an assessment of clinical applicability performed by eight GI clinicians. Quantitatively, the new method produced accurate interpolation values compared to experimental data (mean difference 0.02 ± 0.05 s) and was accurate when applied solely to dysrhythmic data (0.02 ± 0.06 s), both within the error in manual AT marking (mean 0.2 s). Mean interpolation processing time was 6.0 s per wave. CONCLUSION AND SIGNIFICANCE These novel methods provide a validated visualization platform that will improve analysis of high-resolution GI mapping in research and clinical translation.
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Ahn J, Choi MH, Kim K, Senok SS, Cho DID, Koo KI, Goo Y. The advantage of topographic prominence-adopted filter for the detection of short-latency spikes of retinal ganglion cells. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:555-563. [PMID: 28883759 PMCID: PMC5587605 DOI: 10.4196/kjpp.2017.21.5.555] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/03/2017] [Accepted: 08/03/2017] [Indexed: 11/24/2022]
Abstract
Electrical stimulation through retinal prosthesis elicits both short and long-latency retinal ganglion cell (RGC) spikes. Because the short-latency RGC spike is usually obscured by electrical stimulus artifact, it is very important to isolate spike from stimulus artifact. Previously, we showed that topographic prominence (TP) discriminator based algorithm is valid and useful for artifact subtraction. In this study, we compared the performance of forward backward (FB) filter only vs. TP-adopted FB filter for artifact subtraction. From the extracted retinae of rd1 mice, we recorded RGC spikes with 8×8 multielectrode array (MEA). The recorded signals were classified into four groups by distances between the stimulation and recording electrodes on MEA (200-400, 400-600, 600-800, 800-1000 µm). Fifty cathodic phase-1st biphasic current pulses (duration 500 µs, intensity 5, 10, 20, 30, 40, 50, 60 µA) were applied at every 1 sec. We compared false positive error and false negative error in FB filter and TP-adopted FB filter. By implementing TP-adopted FB filter, short-latency spike can be detected better regarding sensitivity and specificity for detecting spikes regardless of the strength of stimulus and the distance between stimulus and recording electrodes.
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Affiliation(s)
- Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
| | - Myoung-Hwan Choi
- Department of Biomedical Engineering, University of Ulsan, Ulsan 44610, Korea
| | - Kwangsoo Kim
- Department of Electronics and Control Engineering, Hanbat National University, Daejeon 34158, Korea
| | - Solomon S Senok
- Ajman University School of Medicine, PO Box 346, Ajman, United Arab Emirates
| | - Dong-Il Dan Cho
- Department of Electrical and Computer Engineering, Seoul National University, Seoul 08826, Korea
| | - Kyo-In Koo
- Department of Biomedical Engineering, University of Ulsan, Ulsan 44610, Korea
| | - Yongsook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
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Angeli TR, Du P, Paskaranandavadivel N, Sathar S, Hall A, Asirvatham SJ, Farrugia G, Windsor JA, Cheng LK, O'Grady G. High-resolution electrical mapping of porcine gastric slow-wave propagation from the mucosal surface. Neurogastroenterol Motil 2017; 29:10.1111/nmo.13010. [PMID: 28035728 PMCID: PMC5393964 DOI: 10.1111/nmo.13010] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/19/2016] [Indexed: 12/12/2022]
Abstract
BACKGROUND Gastric motility is coordinated by bioelectrical slow waves, and gastric dysrhythmias are reported in motility disorders. High-resolution (HR) mapping has advanced the accurate assessment of gastric dysrhythmias, offering promise as a diagnostic technique. However, HR mapping has been restricted to invasive surgical serosal access. This study investigates the feasibility of HR mapping from the gastric mucosal surface. METHODS Experiments were conducted in vivo in 14 weaner pigs. Reference serosal recordings were performed with flexible-printed-circuit (FPC) arrays (128-192 electrodes). Mucosal recordings were performed by two methods: (i) FPC array aligned directly opposite the serosal array, and (ii) cardiac mapping catheter modified for gastric mucosal recordings. Slow-wave propagation and morphology characteristics were quantified and compared between simultaneous serosal and mucosal recordings. KEY RESULTS Slow-wave activity was consistently recorded from the mucosal surface from both electrode arrays. Mucosally recorded slow-wave propagation was consistent with reference serosal activation pattern, frequency (P≥.3), and velocity (P≥.4). However, mucosally recorded slow-wave morphology exhibited reduced amplitude (65-72% reduced, P<.001) and wider downstroke width (18-31% wider, P≤.02), compared to serosal data. Dysrhythmias were successfully mapped and classified from the mucosal surface, accorded with serosal data, and were consistent with known dysrhythmic mechanisms in the porcine model. CONCLUSIONS & INFERENCES High-resolution gastric electrical mapping was achieved from the mucosal surface, and demonstrated consistent propagation characteristics with serosal data. However, mucosal signal morphology was attenuated, demonstrating necessity for optimized electrode designs and analytical algorithms. This study demonstrates feasibility of endoscopic HR mapping, providing a foundation for advancement of minimally invasive spatiotemporal gastric mapping as a clinical and scientific tool.
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Affiliation(s)
- Timothy R. Angeli
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | - Peng Du
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | | | - Shameer Sathar
- Auckland Bioengineering Institute, University of Auckland, New Zealand
| | - Andrew Hall
- Department of Surgery, University of Auckland, New Zealand
| | | | - Gianrico Farrugia
- Department of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, USA
| | | | - Leo K. Cheng
- Auckland Bioengineering Institute, University of Auckland, New Zealand., Department of Surgery, Vanderbilt University, Nashville, TN, USA
| | - Gregory O'Grady
- Auckland Bioengineering Institute, University of Auckland, New Zealand., Department of Surgery, University of Auckland, New Zealand
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Choi MH, Ahn J, Park DJ, Lee SM, Kim K, Cho DID, Senok SS, Koo KI, Goo YS. Topographic prominence discriminator for the detection of short-latency spikes of retinal ganglion cells. J Neural Eng 2017; 14:016017. [DOI: 10.1088/1741-2552/aa5646] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Erickson JC, Putney J, Hilbert D, Paskaranandavadivel N, Cheng LK, O'Grady G, Angeli TR. Iterative Covariance-Based Removal of Time-Synchronous Artifacts: Application to Gastrointestinal Electrical Recordings. IEEE Trans Biomed Eng 2016; 63:2262-2272. [PMID: 26829772 DOI: 10.1109/tbme.2016.2521764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The aim of this study was to develop, validate, and apply a fully automated method for reducing large temporally synchronous artifacts present in electrical recordings made from the gastrointestinal (GI) serosa, which are problematic for properly assessing slow wave dynamics. Such artifacts routinely arise in experimental and clinical settings from motion, switching behavior of medical instruments, or electrode array manipulation. METHODS A novel iterative Covariance-Based Reduction of Artifacts (COBRA) algorithm sequentially reduced artifact waveforms using an updating across-channel median as a noise template, scaled and subtracted from each channel based on their covariance. RESULTS Application of COBRA substantially increased the signal-to-artifact ratio (12.8 ± 2.5 dB), while minimally attenuating the energy of the underlying source signal by 7.9% on average ( -11.1 ± 3.9 dB). CONCLUSION COBRA was shown to be highly effective for aiding recovery and accurate marking of slow wave events (sensitivity = 0.90 ± 0.04; positive-predictive value = 0.74 ± 0.08) from large segments of in vivo porcine GI electrical mapping data that would otherwise be lost due to a broad range of contaminating artifact waveforms. SIGNIFICANCE Strongly reducing artifacts with COBRA ultimately allowed for rapid production of accurate isochronal activation maps detailing the dynamics of slow wave propagation in the porcine intestine. Such mapping studies can help characterize differences between normal and dysrhythmic events, which have been associated with GI abnormalities, such as intestinal ischemia and gastroparesis. The COBRA method may be generally applicable for removing temporally synchronous artifacts in other biosignal processing domains.
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Affiliation(s)
- Jonathan C Erickson
- Department of Physics and Engineering, Washington and Lee University, Lexington, VA, USA
| | - Joy Putney
- Department of Physics and Engineering, Washington and Lee University
| | - Douglas Hilbert
- Departments of Mathematics and Biochemistry, Washington and Lee University
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Du P, Paskaranandavadivel N, Angeli TR, Cheng LK, O'Grady G. The virtual intestine: in silico modeling of small intestinal electrophysiology and motility and the applications. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 8:69-85. [PMID: 26562482 DOI: 10.1002/wsbm.1324] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 10/01/2015] [Accepted: 10/02/2015] [Indexed: 02/06/2023]
Abstract
The intestine comprises a long hollow muscular tube organized in anatomically and functionally discrete compartments, which digest and absorb nutrients and water from ingested food. The intestine also plays key roles in the elimination of waste and protection from infection. Critical to all of these functions is the intricate, highly coordinated motion of the intestinal tract, known as motility, which is coregulated by hormonal, neural, electrophysiological and other factors. The Virtual Intestine encapsulates a series of mathematical models of intestinal function in health and disease, with a current focus on motility, and particularly electrophysiology. The Virtual Intestine is being cohesively established across multiple physiological scales, from sub/cellular functions to whole organ levels, facilitating quantitative evaluations that present an integrative in silico framework. The models are also now finding broad physiological applications, including in evaluating hypotheses of slow wave pacemaker mechanisms, smooth muscle electrophysiology, structure-function relationships, and electromechanical coupling. Clinical applications are also beginning to follow, including in the pathophysiology of motility disorders, diagnosing intestinal ischemia, and visualizing colonic dysfunction. These advances illustrate the emerging potential of the Virtual Intestine to effectively address multiscale research challenges in interdisciplinary gastrointestinal sciences.
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Affiliation(s)
- Peng Du
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | | | - Timothy R Angeli
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Leo K Cheng
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Gregory O'Grady
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
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