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Díaz M, Lucchetti F, Avan P, Giraudet F, Deltenre P, Nonclercq A. Preserved Auditory Steady State Response and Envelope-Following Response in Severe Brainstem Dysfunction Highlight the Need for Cross-Checking. Ear Hear 2024; 45:400-410. [PMID: 37828657 DOI: 10.1097/aud.0000000000001437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
OBJECTIVES Commercially available auditory steady state response (ASSR) systems are widely used to obtain hearing thresholds in the pediatric population objectively. Children are often examined during natural or induced sleep so that the recorded ASSRs are of subcortical origin, the inferior colliculus being often designated as the main ASSR contributor in these conditions. This report presents data from a battery of auditory neurophysiological objective tests obtained in 3 cases of severe brainstem dysfunction in sleeping children. In addition to ASSRs, envelope-following response (EFR) recordings designed to distinguish peripheral (cochlear nerve) from central (brainstem) were recorded to document the effect of brainstem dysfunction on the two types of phase-locked responses. DESIGN Results obtained in the 3 children with severe brainstem dysfunctions were compared with those of age-matched controls. The cases were identified as posterior fossa tumor, undiagnosed (UD), and Pelizaeus-Merzbacher-Like Disease. The standard audiological objective tests comprised tympanograms, distortion product otoacoustic emissions, click-evoked auditory brainstem responses (ABRs), and ASSRs. EFRs were recorded using horizontal (EFR-H) and vertical (EFR-V) channels and a stimulus phase rotation technique allowing isolation of the EFR waveforms in the time domain to obtain direct latency measurements. RESULTS The brainstem dysfunctions of the 3 children were revealed as abnormal (weak, absent, or delayed) ABRs central waves with a normal wave I. In addition, they all presented a summating and cochlear microphonic potential in their ABRs, coupled with a normal wave I, which implies normal cochlear and cochlear nerve function. EFR-H and EFR-V waveforms were identified in the two cases in whom they were recorded. The EFR-Hs onset latencies, response durations, and phase-locking values did not differ from their respective age-matched control values, indicating normal cochlear nerve EFRs. In contrast, the EFR-V phase-locking value and onset latency varied from their control values. Both patients had abnormal but identifiable and significantly phase-locked brainstem EFRs, even in a case with severely distorted ABR central waves. ASSR objective audiograms were recorded in two cases. They showed normal or slightly elevated (explained by a slight transmission loss) thresholds that do not yield any clue about their brainstem dysfunction, revealing the method's lack of sensitivity to severe brainstem dysfunction. CONCLUSIONS The present study, performed on 3 sleeping children with severe brainstem dysfunction but normal cochlear responses (cochlear microphonic potential, summating potential, and ABR wave I), revealed the differential sensitivity of three auditory electrophysiological techniques. Estimated thresholds obtained by standard ASSR recordings (cases UD and Pelizaeus-Merzbacher-Like Disease) provided no clue to the brainstem dysfunction clearly revealed by the click-evoked ABR. EFR recordings (cases posterior fossa tumor and UD) showed preserved central responses with abnormal latencies and low phase-locking values, whereas the peripheral EFR attributed to the cochlear nerve was normal. The one case (UD) for which the three techniques could be performed confirms this sensitivity gradient, emphasizing the need for applying the Cross-Check Principle by avoiding resorting to ASSR recording alone. The entirely normal EFR-H recordings observed in two cases further strengthen the hypothesis of its cochlear nerve origin in sleeping children.
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Affiliation(s)
- Macarena Díaz
- Bio-, Electro- and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Federico Lucchetti
- Critical and Extreme Security and Dependability Group (CritiX), Interdisciplinary Centre for Security, Reliability and Trust, Université du Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Paul Avan
- Department of Neurosensory Biophysics, Institut national de la santé et de la recherche médicale, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Fabrice Giraudet
- Department of Neurosensory Biophysics, Institut national de la santé et de la recherche médicale, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Paul Deltenre
- Laboratoire de Neurophysiologie Sensorielle et Cognitive, Department of Neurology, Brugmann Hospital, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-, Electro- and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
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Dontaine P, Rouge C, Urbain C, Galer S, Raffoul R, Nonclercq A, Van Dyck D, Baijot S, Aeby A. How the Spreading and Intensity of Interictal Epileptic Activity Are Associated with Visuo-Spatial Skills in Children with Self-Limited Focal Epilepsy with Centro-Temporal Spikes. Brain Sci 2023; 13:1566. [PMID: 38002525 PMCID: PMC10669985 DOI: 10.3390/brainsci13111566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 10/20/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
This paper investigates brain-behaviour associations between interictal epileptic discharges and cognitive performance in a population of children with self-limited focal epilepsy with centro-temporal spikes (SeLECTS). Sixteen patients with SeLECTS underwent an extensive neuropsychological assessment, including verbal short-term and episodic memory, non-verbal short-term memory, attentional abilities and executive function. Two quantitative EEG indices were analysed, i.e., the Spike Wave Index (SWI) and the Spike Wave Frequency (SWF), and one qualitative EEG index, i.e., the EEG score, was used to evaluate the spreading of focal SW to other parts of the brain. We investigated associations between EEG indices and neuropsychological performance with non-parametric Spearman correlation analyses, including correction for multiple comparisons. The results showed a significant negative correlation between (i) the awake EEG score and the Block Tapping Test, a visuo-spatial short-term memory task, and (ii) the sleep SWI and the Tower of London, a visuo-spatial planning task (pcorr < 0.05). These findings suggest that, in addition to the usual quantitative EEG indices, the EEG analysis should include the qualitative EEG score evaluating the spreading of focal SW to other parts of the brain and that neuropsychological assessment should include visuo-spatial skills.
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Affiliation(s)
- Pauline Dontaine
- Department of Pediatric Neurology, Hopital Universitaire de Bruxelles (H.U.B.), Queen Fabiola Children’s University Hospital (HUDERF), Université Libre de Bruxelles (ULB), 1020 Brussels, Belgium
| | - Coralie Rouge
- Department of Pediatric Neurology, Hopital Universitaire de Bruxelles (H.U.B.), Queen Fabiola Children’s University Hospital (HUDERF), Université Libre de Bruxelles (ULB), 1020 Brussels, Belgium
- Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition & Neurosciences (CRCN), ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
- Laboratoire de Neuroanatomie et Neuroimagerie Translationnelles (LN2T), UNI-ULB Neurosciences Institute, Hôpital Erasme, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Charline Urbain
- Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition & Neurosciences (CRCN), ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
- Laboratoire de Neuroanatomie et Neuroimagerie Translationnelles (LN2T), UNI-ULB Neurosciences Institute, Hôpital Erasme, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Sophie Galer
- Department of Pediatric Neurology, Hopital Universitaire de Bruxelles (H.U.B.), Queen Fabiola Children’s University Hospital (HUDERF), Université Libre de Bruxelles (ULB), 1020 Brussels, Belgium
- Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition & Neurosciences (CRCN), ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
- Department of Neuropsychology and Speech Therapy, Queen Fabiola Children’s University Hospital (HUDERF)-Hôpital Universitaire de Bruxelles (H.U.B), Université libre de Bruxelles (ULB), 1020 Brussels, Belgium
| | - Romain Raffoul
- BEAMS (Bio-, Electro- And Mechanical Systems), Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Antoine Nonclercq
- BEAMS (Bio-, Electro- And Mechanical Systems), Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Dorine Van Dyck
- Department of Pediatric Neurology, Hopital Universitaire de Bruxelles (H.U.B.), Queen Fabiola Children’s University Hospital (HUDERF), Université Libre de Bruxelles (ULB), 1020 Brussels, Belgium
- Department of Neuropsychology and Speech Therapy, Queen Fabiola Children’s University Hospital (HUDERF)-Hôpital Universitaire de Bruxelles (H.U.B), Université libre de Bruxelles (ULB), 1020 Brussels, Belgium
| | - Simon Baijot
- Department of Pediatric Neurology, Hopital Universitaire de Bruxelles (H.U.B.), Queen Fabiola Children’s University Hospital (HUDERF), Université Libre de Bruxelles (ULB), 1020 Brussels, Belgium
- Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition & Neurosciences (CRCN), ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
- Department of Neuropsychology and Speech Therapy, Queen Fabiola Children’s University Hospital (HUDERF)-Hôpital Universitaire de Bruxelles (H.U.B), Université libre de Bruxelles (ULB), 1020 Brussels, Belgium
| | - Alec Aeby
- Department of Pediatric Neurology, Hopital Universitaire de Bruxelles (H.U.B.), Queen Fabiola Children’s University Hospital (HUDERF), Université Libre de Bruxelles (ULB), 1020 Brussels, Belgium
- Neuropsychology and Functional Neuroimaging Research Group (UR2NF), Center for Research in Cognition & Neurosciences (CRCN), ULB Neurosciences Institute, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
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Vespa S, Stumpp L, Liberati G, Delbeke J, Nonclercq A, Mouraux A, El Tahry R. Corrigendum to "Characterization of vagus nerve stimulation-induced pupillary responses in epileptic patients" [Brain Stimul. 15 (2022) 1498-1507]. Brain Stimul 2023; 16:1461. [PMID: 37793267 DOI: 10.1016/j.brs.2023.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/06/2023] Open
Affiliation(s)
- Simone Vespa
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium.
| | - Lars Stumpp
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | - Giulia Liberati
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | - Jean Delbeke
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | | | - André Mouraux
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | - Riëm El Tahry
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium; Department of Neurology, Saint Luc University Hospital, Brussels, Belgium
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Germany E, Teixeira I, Danthine V, Santalucia R, Cakiroglu I, Torres A, Verleysen M, Delbeke J, Nonclercq A, Tahry RE. Functional brain connectivity indexes derived from low-density EEG of pre-implanted patients as VNS outcome predictors. J Neural Eng 2023; 20:046039. [PMID: 37595607 DOI: 10.1088/1741-2552/acf1cd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 08/18/2023] [Indexed: 08/20/2023]
Abstract
Objective. In 1/3 of patients, anti-seizure medications may be insufficient, and resective surgery may be offered whenever the seizure onset is localized and situated in a non-eloquent brain region. When surgery is not feasible or fails, vagus nerve stimulation (VNS) therapy can be used as an add-on treatment to reduce seizure frequency and/or severity. However, screening tools or methods for predicting patient response to VNS and avoiding unnecessary implantation are unavailable, and confident biomarkers of clinical efficacy are unclear.Approach. To predict the response of patients to VNS, functional brain connectivity measures in combination with graph measures have been primarily used with respect to imaging techniques such as functional magnetic resonance imaging, but connectivity graph-based analysis based on electrophysiological signals such as electroencephalogram, have been barely explored. Although the study of the influence of VNS on functional connectivity is not new, this work is distinguished by using preimplantation low-density EEG data to analyze discriminative measures between responders and non-responder patients using functional connectivity and graph theory metrics.Main results. By calculating five functional brain connectivity indexes per frequency band upon partial directed coherence and direct transform function connectivity matrices in a population of 37 refractory epilepsy patients, we found significant differences (p< 0.05) between the global efficiency, average clustering coefficient, and modularity of responders and non-responders using the Mann-Whitney U test with Benjamini-Hochberg correction procedure and use of a false discovery rate of 5%.Significance. Our results indicate that these measures may potentially be used as biomarkers to predict responsiveness to VNS therapy.
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Affiliation(s)
- Enrique Germany
- IoNS, Universite Catholique de Louvain, Brussels, Belgium
- WELBIO Department, WEL Research Institute, Wavre, Belgium
| | - Igor Teixeira
- IoNS, Universite Catholique de Louvain, Brussels, Belgium
| | | | | | - Inci Cakiroglu
- IoNS, Universite Catholique de Louvain, Brussels, Belgium
| | - Andres Torres
- IoNS, Universite Catholique de Louvain, Brussels, Belgium
| | | | - Jean Delbeke
- IoNS, Universite Catholique de Louvain, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-Electro-and Mechanical Systems (BEAMS), Université Libre de Bruxelles, Brussels, Belgium
| | - Riëm El Tahry
- IoNS, Universite Catholique de Louvain, Brussels, Belgium
- WELBIO Department, WEL Research Institute, Wavre, Belgium
- Cliniques Universitaires Saint-Luc, Brussels, Belgium
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Verstraeten M, Boukheir G, Vande Perre L, Raffoul R, Chavez J, Delchambre A, Roumeguere T, Vanhoestenberghe A, Nonclercq A. Urinary Bladder Phantom Mimicking Mechanical Properties and Pressure During Filling. Biomed Phys Eng Express 2023. [PMID: 37406619 DOI: 10.1088/2057-1976/ace449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Abstract
OBJECTIVE Phantoms that mimic healthy or diseased organ properties can complement animal models for surgical planning, training, and medical device development. If urodynamic studies rely on pressure-volume curves to assess lower urinary tract symptoms, there is an unsatisfied need for a bladder phantom that accurately mimics the bladder stretching capabilities and compliant behaviour during physiological filling. 
Approach: We demonstrate the suitability of water-soluble 3D-printed moulds as a versatile method to fabricate accurate phantoms with anatomical structures reconstructed from medical images. We report a phantom fabricated with silicone rubber. A wire net limits the silicone expansion to model the cystometric capacity. A mathematical model describes the pressure increase due to passive hyperelastic properties. 
Main results: The phantom reproduces the bladder's mechanical properties during filling. The pressure-volume curve measured on the phantom is typical of cystometric studies, with a compliance of 25.2 ± 1 mL cmH_2O^(-1). The root-mean-square error between the theoretical model and experimental data is 2.7 cmH_2O. The compliance, bladder wall thickness, cystometric capacity and pressure near the cystometric capacity of the phantom can be tuned to mimic various pathologies or human variability. 
Significance: The manufacturing method is suitable for fabricating bladder and other soft and hollow organ phantoms. The mathematical model provides a method to determine design parameters to model healthy or diseased bladders. Soft hollow organ phantoms can be used to complement animal experimentations for developing and validating medical devices aiming to be anchored on these organs or monitor their activity through pressure and strain measurement. 
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Affiliation(s)
- Maxime Verstraeten
- BEAMS Bio-Mechatronics, Université Libre de Bruxelles École polytechnique de Bruxelles, Avenue F. D. Roosevelt 50, 1050 Bruxelles, CP165/56, Bruxelles, Bruxelles, 1050, BELGIUM
| | - George Boukheir
- Department of Urology, Hopital Erasme, Route de Lennik 808, Bruxelles, Bruxelles, 1070, BELGIUM
| | - Louis Vande Perre
- BEAMS Bio-Mechatronics, Université Libre de Bruxelles École polytechnique de Bruxelles, Avenue F. D. Roosevelt 50, 1050 Bruxelles, CP165/56, Bruxelles, Bruxelles, 1050, BELGIUM
| | - Romain Raffoul
- BEAMS Bio-Mechatronics, Université Libre de Bruxelles École polytechnique de Bruxelles, Avenue F. D. Roosevelt 50, 1050 Bruxelles, CP165/56, Bruxelles, Bruxelles, 1050, BELGIUM
| | - Javier Chavez
- BEAMS Bio-Mechatronics, Université Libre de Bruxelles École polytechnique de Bruxelles, Avenue F. D. Roosevelt 50, 1050 Bruxelles, CP165/56, Bruxelles, Bruxelles, 1050, BELGIUM
| | - Alain Delchambre
- BEAMS Bio-Mechatronics, Université Libre de Bruxelles École polytechnique de Bruxelles, Avenue F. D. Roosevelt 50, 1050 Bruxelles, CP165/56, Bruxelles, Bruxelles, 1050, BELGIUM
| | - Thierry Roumeguere
- Department of Urology, Hopital Erasme, Route de Lennik 808, Bruxelles, Bruxelles, 1070, BELGIUM
| | - Anne Vanhoestenberghe
- King's College London, King's College London, Becket House, 9th Floor, Office 3 1 Lambeth Palace Rd, London, WC2R 2LS, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Antoine Nonclercq
- BEAMS Bio-Mechatronics, Université Libre de Bruxelles École polytechnique de Bruxelles, Avenue F. D. Roosevelt 50, 1050 Bruxelles, CP165/56, Bruxelles, Bruxelles, 1050, BELGIUM
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Decroly G, Hassen RB, Achten WMJ, Grimaldi D, Gaspard N, Deviere J, Delchambre A, Nonclercq A. Strong Sustainability of Medical Technologies: A Medical Taboo? The Case of Disposable Endoscopes. Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-7. [PMID: 38083580 DOI: 10.1109/embc40787.2023.10341135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
This paper aims to question the sustainability of biomedical engineering practices. The strong sustainability framework is applied to the evaluation and development of medical technologies through the definition of clinical sustainability. A roadmap for developing and evaluating medical technologies in this respect is derived from this framework, as a first step toward a multidisciplinary evaluation tool. On this basis, the current trend towards disposable endoscopes is analyzed and discussed. This highlights the subtle balance between economic, clinical, social, and environmental factors, the lack of evidence at these multiple levels, and the need for multidisciplinarity. This paper concludes with the need to assess all aspects of sustainability and identify and quantify the trade-offs, instead of focusing on one or two key indicators, to have more relevant information in order to make better and more effective decisions. Towards sustainable healthcare, we outline two paths of action: (1) providing evidence that is lacking on the environmental impact of existing or currently developed medical technologies and (2) clarifying the premises and visions underlying our practices.Clinical Relevance- This work provides insights regarding the strong sustainability of medical technologies. This clinical framework may help clinicians and developers in decision-making to reduce indirect negative ecological, social, and health impacts.
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Perre LV, Chavez Cerda J, Verstraeten M, Raffoul R, Delbeke J, Tahry RE, Nonclercq A, Gorza SP. Heat accumulation during infrared stimulation impacts the response of ex vivo rat sciatic nerve. Annu Int Conf IEEE Eng Med Biol Soc 2023; 2023:1-4. [PMID: 38083348 DOI: 10.1109/embc40787.2023.10340444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Infrared neural stimulation (INS) is a neuromodulation technique that involves short optical pulses delivered to the neural tissue, resulting in the initiation of action potentials. In this work, we studied the compound neural action potentials (CNAP) generated by INS in five ex vivo sciatic nerves. A 1470 nm laser emitting a sequence of 0.4 ms light pulses with a peak power of 10 W was used. A single 4 mJ stimulus is not capable of eliciting a nerve response. However, repetition of the optical stimuli resulted in the induction of CNAPs. Heat accumulation induced by repetition rates as high as 10 Hz may be involved in the increase in CNAP amplitude. This sensitization effect may help to reduce the pulse energy required to evoke CNAP. In addition, these results highlight the importance of investigating the role of the slow nerve temperature dynamics in INS.
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Berger A, Carapancea E, Vespa S, Danthine V, Doguet P, Delbeke J, Nonclercq A, El Tahry R. Vagus nerve stimulation-induced laryngeal motor evoked potentials for response prediction and intensity titration in drug-resistant epilepsy. Clin Neurophysiol 2023; 147:99-107. [PMID: 36764043 DOI: 10.1016/j.clinph.2023.01.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 12/07/2022] [Accepted: 01/19/2023] [Indexed: 01/29/2023]
Abstract
OBJECTIVE The objective of the study was to record Laryngeal Motor Evoked Potentials (LMEPs) in Vagus Nerve Stimulation (VNS)-implanted patients suffering from Drug-Resistant Epilepsy (DRE). Based on these recordings, LMEPs characteristics were evaluated and compared between responders (R) and non-responders (NR). Finally, possible under- or over-stimulation was assessed based on a physiological indicator of fiber engagement. METHODS Mean dose-response curves were compared between R and NR. A Support Vector Machine (SVM) model was built based on both LMEP and dose-response curves features, to discriminate R from NR. For the exploration of possible under- or over-stimulation, a ratio between the clinically applied stimulation intensity and the intensity yielding to LMEP saturation was computed for each patient. RESULTS A trend towards a greater excitability of the nerve was observed in R compared to NR. The SVM classifier discriminated R and NR with an accuracy of 80%. An ineffective attempt to overstimulate at current levels above what is usually necessary to obtain clinical benefits was suggested in NR. CONCLUSIONS The SVM model built emphasizes a possible link between vagus nerve recruitment characteristics and treatment effectiveness. Most of the clinically responding patients receive VNS at a stimulation intensity 1-fold and 2-fold the intensity inducing LMEP saturation. SIGNIFICANCE LMEP saturation could be a practical help in guiding the titration of the stimulation parameters using a physiological indicator of fiber engagement.
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Affiliation(s)
- Alexandre Berger
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Synergia Medical SA, Mont-Saint-Guibert, Belgium; Sleep and Chronobiology Lab, GIGA-Institute, CRC-In Vivo Imaging Unit, University of Liège, Liège, Belgium.
| | - Evelina Carapancea
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Simone Vespa
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Venethia Danthine
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | | | - Jean Delbeke
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Institute of Neuroscience, LCEN3, Department of Neurology, Ghent University, Ghent, Belgium
| | - Antoine Nonclercq
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Brussels, Belgium
| | - Riëm El Tahry
- Institute of Neuroscience (IoNS), Department of Clinical Neuroscience, Université Catholique de Louvain, Brussels, Belgium; Center for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium; Walloon Excellence in Life Sciences and Biotechnology (WELBIO) Department, WEL Research Institute, Avenue Pasteur 6, 1300 Wavre, Belgium
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Vespa S, Stumpp L, Liberati G, Delbeke J, Nonclercq A, Mouraux A, El Tahry R. Characterization of vagus nerve stimulation-induced pupillary responses in epileptic patients. Brain Stimul 2022; 15:1498-1507. [PMID: 36402376 DOI: 10.1016/j.brs.2022.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 10/15/2022] [Accepted: 11/13/2022] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Modulation of the locus coeruleus (LC)-noradrenergic system is a key mechanism of vagus nerve stimulation (VNS). Activation of the LC produces pupil dilation, and the VNS-induced change in pupil diameter was demonstrated in animals as a possible dose-dependent biomarker for treatment titration. OBJECTIVE This study aimed to characterize VNS-induced pupillary responses in epileptic patients. METHODS Pupil diameter was recorded in ten epileptic patients upon four stimulation conditions: three graded levels of VNS intensity and a somatosensory control stimulation (cutaneous electrical stimulation over the left clavicle). For each block, the patients rated the intensity of stimulation on a numerical scale. We extracted the latency of the peak pupil dilation and the magnitude of the early (0-2.5 s) and late components (2.5-5 s) of the pupil dilation response (PDR). RESULTS VNS elicited a peak dilation with longer latency compared to the control condition (p = 0.043). The magnitude of the early PDR was significantly correlated with the intensity of perception (p = 0.046), whereas the late PDR was not (p = 0.19). There was a significant main effect of the VNS level of intensity on the magnitude of the late PDR (p = 0.01) but not on the early PDR (p = 0.2). The relationship between late PDR magnitude and VNS intensity was best fit by a Gaussian model (inverted-U). CONCLUSIONS The late component of the PDR might reflect specific dose-dependent effects of VNS, as compared to control somatosensory stimulation. The inverted-U relationship of late PDR with VNS intensity might indicate the engagement of antagonist central mechanisms at high stimulation intensities.
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Affiliation(s)
- Simone Vespa
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium.
| | - Lars Stumpp
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | - Giulia Liberati
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | - Jean Delbeke
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | | | - André Mouraux
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium
| | - Riëm El Tahry
- Institute of NeuroScience, Catholic University of Louvain, Brussels, Belgium; Department of Neurology, Saint Luc University Hospital, Brussels, Belgium
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Cury J, Smets H, Bouzin C, Doguet P, Vanhoestenberghe A, Delbeke J, Tahry RE, Nonclercq A, Gorza SP. Optical birefringence changes in myelinated and unmyelinated nerves: A comparative study. J Biophotonics 2022; 15:e202200028. [PMID: 35703916 DOI: 10.1002/jbio.202200028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 05/30/2022] [Accepted: 06/07/2022] [Indexed: 06/15/2023]
Abstract
The measurement of birefringence variations related to nerve activity is a promising label-free technique for sensing compound neural action potentials (CNAPs). While widely applied in crustaceans, little is known about its efficiency on mammal peripheral nerves. In this work, birefringence recordings to detect CNAPs, and Stokes parameters measurements were performed in rat and lobster nerves. While single-trial detection of nerve activity in crustaceans was achieved successfully, no optical signal was detected in rats, even after extensive signal filtering and averaging. The Stokes parameters showed that a high degree of polarization of light is maintained in lobster sample, whereas an almost complete light depolarization occurs in rat nerve. Our results indicate that depolarization itself is not sufficient to explain the absence of birefringence signals in rats. We hypothesize that this absence comes from the myelin sheets, which constraint the birefringence changes to only take place at the nodes of Ranvier.
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Affiliation(s)
- Joaquín Cury
- Opera-photonics, Université Libre de Bruxelles, Brussels, Belgium
- Bio-, Electro- and Mechanical Systems (BEAMS), Université Libre de Bruxelles, Brussels, Belgium
| | - Hugo Smets
- Bio-, Electro- and Mechanical Systems (BEAMS), Université Libre de Bruxelles, Brussels, Belgium
| | - Caroline Bouzin
- Université Catholique de Louvain, Institut de Recherche Expérimentale et Clinique (IREC), IREC Imaging Platform (2IP), Brussels, Belgium
| | | | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, University College of London, London, UK
| | - Jean Delbeke
- Department of Neurology, Institute of Neurosciences (IONS), Université Catholique de Louvain, Cliniques Universitaires Saint Luc, Brussels, Belgium
| | - Riëm El Tahry
- Department of Neurology, Institute of Neurosciences (IONS), Université Catholique de Louvain, Cliniques Universitaires Saint Luc, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-, Electro- and Mechanical Systems (BEAMS), Université Libre de Bruxelles, Brussels, Belgium
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11
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Ferlini L, Nonclercq A, Su F, Creteur J, Taccone FS, Gaspard N. Sepsis modulates cortical excitability and alters the local and systemic hemodynamic response to seizures. Sci Rep 2022; 12:11336. [PMID: 35790848 PMCID: PMC9256588 DOI: 10.1038/s41598-022-15426-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 06/23/2022] [Indexed: 11/09/2022] Open
Abstract
Non-convulsive seizures and status epilepticus are frequent and associated with increased mortality in septic patients. However, the mechanism through which seizures impact outcome in these patients is unclear. As previous studies yielded an alteration of neurovascular coupling (NVC) during sepsis, we hypothesized that non-convulsive seizures, might further impair NVC, leading to brain tissue hypoxia. We used a previously developed ovine model of sepsis. Animals were allocated to sham procedure or sepsis; septic animals were studied either during the hyperdynamic phase (sepsis group) or after septic shock occurrence (septic shock group). After allocation, seizures were induced by cortical application of penicillin. We recorded a greater seizure-induced increase in the EEG gamma power in the sepsis group than in sham. Using a neural mass model, we also found that the theoretical activity of the modeled inhibitory interneurons, thought to be important to reproduce gamma oscillations, were relatively greater in the sepsis group. However, the NVC was impaired in sepsis animals, despite a normal brain tissue oxygenation. In septic shock animals, it was not possible to induce seizures. Cortical activity declined in case of septic shock, but it did not differ between sham or sepsis animals. As the alteration in NVC preceded cortical activity reduction, we suggest that, during sepsis progression, the NVC inefficiency could be partially responsible for the alteration of brain function, which might prevent seizure occurrence during septic shock. Moreover, we showed that cardiac output decreased during seizures in sepsis animals instead of increasing as in shams. The alteration of the seizure-induced systemic hemodynamic variations in sepsis might further affect cerebrovascular response to neuronal activation. Our findings support the hypothesis that anomalies in the cerebral blood flow regulation may contribute to the sepsis-associated encephalopathy and that seizures might be dangerous in such a vulnerable setting.
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Affiliation(s)
- Lorenzo Ferlini
- Department of Neurology, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-, Electro- And Mechanical Systems (BEAMS), Université Libre de Bruxelles, Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium
| | - Fuhong Su
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Jacques Creteur
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Erasme Hospital, Université Libre de Bruxelles, Route de Lennik, 808, 1070, Brussels, Belgium.
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12
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Smets H, Stumpp L, Chavez J, Cury J, Vande Perre L, Doguet P, Vanhoestenberghe A, Delbeke J, El Tahry R, Nonclercq A. Chronic recording of the vagus nerve to analyze modulations by the light-dark cycle. J Neural Eng 2022; 19. [PMID: 35764074 DOI: 10.1088/1741-2552/ac7c8f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 06/28/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The vagus nerve is considered to play a key role in the circadian rhythm. Chronic continuous analysis of the vagus nerve activity could contribute to a better understanding of the role of the vagus nerve in light-dark modulations. This paper presents a continuous analysis of spontaneous vagus nerve activity performed in four rats. APPROACH We analyzed the vagus electroneurogram (VENG) and electroencephalogram (EEG) over a recording period of 28 days. Spike activity and heart rate estimation were derived from the VENG, and slow-wave activity was derived from the EEG. The presence of repetitive patterns was investigated with periodograms, cosinor fitting, autocorrelation, and statistical tests. The light-dark variations derived from the VENG spikes were compared with EEG slow waves, an established metric in circadian studies. RESULTS Our results demonstrate that light-dark variations can be detected in long-term vagus nerve activity monitoring. A recording period of about seven days is required to characterize accurately the VENG light-dark variations. SIGNIFICANCE As a major outcome of this study, vagus nerve recordings hold the promise to help understand circadian regulation.
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Affiliation(s)
- Hugo Smets
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Bruxelles, 1050, BELGIUM
| | - Lars Stumpp
- IONS, Université catholique de Louvain, Avenue Mounier 53/B1.53.05, Brussels, 1200, BELGIUM
| | - Javier Chavez
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Bruxelles, 1050, BELGIUM
| | - Joaquin Cury
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Bruxelles, 1050, BELGIUM
| | - Louis Vande Perre
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Bruxelles, 1050, BELGIUM
| | - Pascal Doguet
- Synergia Medical SA, Rue Emile Francqui 6, Mont-Saint-Guibert, 1435, BELGIUM
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, University College London, Brockley Hill, Aspire Create - IOMS BUilding, RNOH campus, London, HA74LP, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Jean Delbeke
- Private Address - Belgium, Seringenstraat 27, Kraainem, B-1950, BELGIUM
| | - Riëm El Tahry
- IONS, Université catholique de Louvain, Avenue Mounier 53/B1.53.05, Brussels, 1200, BELGIUM
| | - Antoine Nonclercq
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Bruxelles, 1050, BELGIUM
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Van Hecke A, Nebbioso A, Santalucia R, Vermeiren J, De Tiège X, Nonclercq A, Van Bogaert P, Aeby A. The EEG score is diagnostic of continuous spike and waves during sleep (CSWS) syndrome. Clin Neurophysiol 2022; 138:132-133. [DOI: 10.1016/j.clinph.2022.03.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Accepted: 03/13/2022] [Indexed: 11/03/2022]
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14
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Debelle A, Hesta M, de Rooster H, Bianchini E, Vanhoestenberghe A, Stock E, Vanderperren K, Polis I, Smets H, Cury J, Acuña V, Delchambre A, Innocenti B, Devière J, Nonclercq A. Impact of adaptive gastric electrical stimulation on weight, food intake, and food intake rate in dogs. Artif Organs 2021; 46:1055-1067. [PMID: 34932224 DOI: 10.1111/aor.14156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 11/04/2021] [Accepted: 12/07/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Gastric electrical stimulation (GES) has been studied for decades as a promising treatment for obesity. Stimulation pulses with fixed amplitude and pulse width are usually applied, but these have limitations with regard to overcoming habituation to GES and inter-subject variation. This study aims to analyze the efficacy of an adaptive GES protocol for reducing food intake and maintaining lean weight in dogs. METHODS Six beagle dogs were implanted with a remotely programmable gastric stimulator. An adaptive protocol was designed to increase the stimulation energy proportionally to the excess of food consumption, with respect to the dogs' maintenance energy requirements. After surgery and habituation to experimental conditions, the dogs went through both a control and a stimulation period of 4 weeks each, in a randomized order. The stimulation parameters were adapted daily. Body weight, food intake, food intake rate, and postprandial cutaneous electrogastrograms (EGG) were recorded to assess the effect of adaptive GES. RESULTS Adaptive GES decreased food intake and food intake rate (p < 0.05) resulting in weight maintenance. In the absence of GES, the dogs gained weight (p < 0.05). Postprandial EGG dominant frequency was accelerated by GES (p < 0.05). The strategy of adapting the stimulation energy was effective in causing significant mid-term changes. CONCLUSION Adaptive GES is effective for reducing food intake and maintaining lean weight. The proposed adaptive strategy may offer benefits to counter habituation and adapt to inter-subject variation in clinical use of GES for obesity.
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Affiliation(s)
- Adrien Debelle
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
| | - Myriam Hesta
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Hilde de Rooster
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Erika Bianchini
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, Department of Materials and Tissue, University College London, Stanmore, UK
| | - Emmelie Stock
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Katrien Vanderperren
- Department of Veterinary Medical Imaging and Small Animal Orthopedics, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Ingeborgh Polis
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Hugo Smets
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
| | - Joaquin Cury
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
| | - Vicente Acuña
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
| | - Alain Delchambre
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
| | - Bernardo Innocenti
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
| | - Jacques Devière
- Department of Gastroenterology, Hepatopancreatology, and Digestive Oncology, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems Department, Ecole polytechnique de Bruxelles, Université libre de Bruxelles, Brussels, Belgium
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15
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Rabineau J, Nonclercq A, Leiner T, van de Borne P, Migeotte PF, Haut B. Closed-Loop Multiscale Computational Model of Human Blood Circulation. Applications to Ballistocardiography. Front Physiol 2021; 12:734311. [PMID: 34955874 PMCID: PMC8697684 DOI: 10.3389/fphys.2021.734311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
Cardiac mechanical activity leads to periodic changes in the distribution of blood throughout the body, which causes micro-oscillations of the body's center of mass and can be measured by ballistocardiography (BCG). However, many of the BCG findings are based on parameters whose origins are poorly understood. Here, we generate simulated multidimensional BCG signals based on a more exhaustive and accurate computational model of blood circulation than previous attempts. This model consists in a closed loop 0D-1D multiscale representation of the human blood circulation. The 0D elements include the cardiac chambers, cardiac valves, arterioles, capillaries, venules, and veins, while the 1D elements include 55 systemic and 57 pulmonary arteries. The simulated multidimensional BCG signal is computed based on the distribution of blood in the different compartments and their anatomical position given by whole-body magnetic resonance angiography on a healthy young subject. We use this model to analyze the elements affecting the BCG signal on its different axes, allowing a better interpretation of clinical records. We also evaluate the impact of filtering and healthy aging on the BCG signal. The results offer a better view of the physiological meaning of BCG, as compared to previous models considering mainly the contribution of the aorta and focusing on longitudinal acceleration BCG. The shape of experimental BCG signals can be reproduced, and their amplitudes are in the range of experimental records. The contributions of the cardiac chambers and the pulmonary circulation are non-negligible, especially on the lateral and transversal components of the velocity BCG signal. The shapes and amplitudes of the BCG waveforms are changing with age, and we propose a scaling law to estimate the pulse wave velocity based on the time intervals between the peaks of the acceleration BCG signal. We also suggest new formulas to estimate the stroke volume and its changes based on the BCG signal expressed in terms of acceleration and kinetic energy.
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Affiliation(s)
- Jeremy Rabineau
- TIPs, Université Libre de Bruxelles, Brussels, Belgium
- LPHYS, Université Libre de Bruxelles, Brussels, Belgium
| | | | - Tim Leiner
- Department of Radiology, Utrecht University Medical Center, Utrecht, Netherlands
| | - Philippe van de Borne
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | | | - Benoit Haut
- TIPs, Université Libre de Bruxelles, Brussels, Belgium
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16
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Evelina I, Vespa S, Danthine V, Stumpp L, Dumoulin M, Berger A, Delbeke J, Nonclercq A, El Tahry R. Vagus nerve stimulation-induced laryngeal motor evoked potentials: a biomarker of effective nerve activation. Brain Stimul 2021. [DOI: 10.1016/j.brs.2021.10.210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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17
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Stumpp L, Smets H, Vespa S, Cury J, pascal doguet, Jean delbeke, Nonclercq A, Riëm ET. Vagus nerve electroneurogram-based detection of acute pentylenetetrazol induced seizures in rats. Brain Stimul 2021. [DOI: 10.1016/j.brs.2021.10.453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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18
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Vespa S, Heyse J, Stumpp L, Liberati G, Santos SF, Rooijakkers H, Nonclercq A, Mouraux A, van Mierlo P, El Tahry R. Vagus Nerve Stimulation elicits sleep EEG desynchronization and network changes in responder patients in epilepsy. Brain Stimul 2021. [DOI: 10.1016/j.brs.2021.10.128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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19
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Vespa S, Heyse J, Stumpp L, Liberati G, Ferrao Santos S, Rooijakkers H, Nonclercq A, Mouraux A, van Mierlo P, El Tahry R. Vagus Nerve Stimulation Elicits Sleep EEG Desynchronization and Network Changes in Responder Patients in Epilepsy. Neurotherapeutics 2021; 18:2623-2638. [PMID: 34668148 PMCID: PMC8804116 DOI: 10.1007/s13311-021-01124-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2021] [Indexed: 12/23/2022] Open
Abstract
Neural desynchronization was shown as a key mechanism of vagus nerve stimulation (VNS) action in epilepsy, and EEG synchronization measures are explored as possible response biomarkers. Since brain functional organization in sleep shows different synchrony and network properties compared to wakefulness, we aimed to explore the effects of acute VNS on EEG-derived measures in the two different states of vigilance. EEG epochs were retrospectively analyzed from twenty-four VNS-treated epileptic patients (11 responders, 13 non-responders) in calm wakefulness and stage N2 sleep. Weighted Phase Lag Index (wPLI) was computed as connectivity measure of synchronization, for VNS OFF and VNS ON conditions. Global efficiency (GE) was computed as a network measure of integration. Ratios OFF/ON were obtained as desynchronization/de-integration index. Values were compared between responders and non-responders, and between EEG states. ROC curve and area-under-the-curve (AUC) analysis was performed for response classification. In responders, stronger VNS-induced theta desynchronization (p < 0.05) and decreased GE (p < 0.05) were found in sleep, but not in wakefulness. Theta sleep wPLI Ratio OFF/ON yielded an AUC of 0.825, and 79% accuracy as a response biomarker if a cut-off value is set at 1.05. Considering all patients, the VNS-induced GE decrease was significantly more important in sleep compared to awake EEG state (p < 0.01). In conclusion, stronger sleep EEG desynchronization in theta band distinguishes responders to VNS therapy from non-responders. VNS-induced reduction of network integration occurs significantly more in sleep than in wakefulness.
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Affiliation(s)
- Simone Vespa
- Institute of Neuroscience (IONS), Université Catholique de Louvain, Avenue Mounier, 53 - 1200, Brussels, Belgium.
| | - Jolan Heyse
- Medical Image and Signal Processing Group (MEDISIP), Ghent University, Ghent, Belgium
| | - Lars Stumpp
- Institute of Neuroscience (IONS), Université Catholique de Louvain, Avenue Mounier, 53 - 1200, Brussels, Belgium
| | - Giulia Liberati
- Institute of Neuroscience (IONS), Université Catholique de Louvain, Avenue Mounier, 53 - 1200, Brussels, Belgium
| | - Susana Ferrao Santos
- Institute of Neuroscience (IONS), Université Catholique de Louvain, Avenue Mounier, 53 - 1200, Brussels, Belgium
- Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Herbert Rooijakkers
- Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems (BEAMS), Université Libre de Bruxelles, Brussels, Belgium
| | - André Mouraux
- Institute of Neuroscience (IONS), Université Catholique de Louvain, Avenue Mounier, 53 - 1200, Brussels, Belgium
| | - Pieter van Mierlo
- Medical Image and Signal Processing Group (MEDISIP), Ghent University, Ghent, Belgium
| | - Riëm El Tahry
- Institute of Neuroscience (IONS), Université Catholique de Louvain, Avenue Mounier, 53 - 1200, Brussels, Belgium
- Centre for Refractory Epilepsy, Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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20
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Haut B, Nonclercq A, Buess A, Rabineau J, Rigaut C, Sobac B. Comprehensive Analysis of Heat and Water Exchanges in the Human Lungs. Front Physiol 2021; 12:649497. [PMID: 34168568 PMCID: PMC8217871 DOI: 10.3389/fphys.2021.649497] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 04/14/2021] [Indexed: 11/13/2022] Open
Abstract
This work presents a new mathematical model of the heat and water exchanges in the human lungs (newborn to adult). This model is based on a local description of the water and energy transports in both the lumen and the surrounding tissues, and is presented in a comprehensive, dimensionless framework with explicitly stated assumptions and a strong physiological background. The model is first used to analyze and quantify the key phenomena and dimensionless numbers governing these heat and water exchanges and then it is applied to an adult in various situations (varying atmospheric conditions, exercising…). The results highlight several interesting physiological elements. They show that the bronchial region of the lungs is able to condition the air in all the considered situations even if, sometimes, for instance when exercising, distal generations have to be involved. The model also shows that these distal generations are super-conditioners. Moreover, the results quantify the key role of the submucosal glands in mucus hydration. They also show that, during expiration, a significant cooling of the air and condensation of water occur along the respiratory tract as the vascularization of the tissues surrounding the airways is not able to maintain these tissues at body temperature during inspiration. Due to the interaction between several phenomena, it appears that the ratio of the amount of water returned to the mucosa during expiration to the amount extracted during inspiration is almost independent of the breathing conditions (around 33%). The results also show that, in acute situations, such as suffering from a pathology with airway dysfunction, when being intubated or when exercising above an intensity threshold, the heat and water exchanges in the lungs may be critical regarding mucus hydration. In proximal generations, the evaporation may overwhelm the ability of the submucosal glands to replenish the airway surface liquid with water. In some situations, the cooling of the mucosa may be very important; it can even become colder than the inspired air, due to evaporative cooling. Finally, the results show that breathing cold air can significantly increase the exchanges between the lungs and the environment, which can be critical regarding disease transmission.
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Affiliation(s)
- Benoit Haut
- Ecole Polytechnique de Bruxelles, Transfers, Interfaces and Processes (TIPs), Université libre de Bruxelles, Brussels, Belgium
| | - Antoine Nonclercq
- Ecole Polytechnique de Bruxelles, Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
| | - Alexandra Buess
- Ecole Polytechnique de Bruxelles, Transfers, Interfaces and Processes (TIPs), Université libre de Bruxelles, Brussels, Belgium
| | - Jérémy Rabineau
- Ecole Polytechnique de Bruxelles, Transfers, Interfaces and Processes (TIPs), Université libre de Bruxelles, Brussels, Belgium
| | - Clément Rigaut
- Ecole Polytechnique de Bruxelles, Transfers, Interfaces and Processes (TIPs), Université libre de Bruxelles, Brussels, Belgium
| | - Benjamin Sobac
- Ecole Polytechnique de Bruxelles, Transfers, Interfaces and Processes (TIPs), Université libre de Bruxelles, Brussels, Belgium.,Université de Pau et des Pays de l'Adour, E2S UPPA, CNRS, Total, LFCR, Anglet, France
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21
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Stumpp L, Smets H, Vespa S, Cury J, Doguet P, Delbeke J, Nonclercq A, El Tahry R. Vagus Nerve Electroneurogram-Based Detection of Acute Pentylenetetrazol Induced Seizures in Rats. Int J Neural Syst 2021; 31:2150024. [PMID: 34030610 DOI: 10.1142/s0129065721500246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
On-demand stimulation improves the efficacy of vagus nerve stimulation (VNS) in refractory epilepsy. The vagus nerve is the main peripheral parasympathetic connection and seizures are known to exhibit autonomic symptoms. Therefore, we hypothesized that seizure detection is possible through vagus nerve electroneurogram (VENG) recording. We developed a metric able to measure abrupt changes in amplitude and frequency of spontaneous vagus nerve action potentials. A classifier was trained using a "leave-one-out" method on a set of 6 seizures and 3 control recordings to utilize the VENG spike feature-based metric for seizure detection. We were able to detect pentylenetetrazol (PTZ) induced acute seizures in 6/6 animals during different stages of the seizure with no false detection. The classifier detected the seizure during an early stage in 3/6 animals and at the onset of tonic clonic stage of the seizure in 3/6 animals. EMG and motion artefacts often accompany epileptic activity. We showed the "epileptic" neural signal to be independent from EMG and motion artefacts. We confirmed the existence of seizure related signals in the VENG recording and proved their applicability for seizure detection. This detection might be a promising tool to improve efficacy of VNS treatment by developing new responsive stimulation systems.
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Affiliation(s)
- Lars Stumpp
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Hugo Smets
- BEAMS Department, Université libre de Bruxelles, Brussels, Belgium
| | - Simone Vespa
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | - Joaquin Cury
- BEAMS Department, Université libre de Bruxelles, Brussels, Belgium
| | | | - Jean Delbeke
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium
| | | | - Riem El Tahry
- Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium.,Cliniques Universitaires Saint Luc, Center for Refractory Epilepsy, Brussels, Belgium
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Debelle A, de Rooster H, Bianchini E, Lonys L, Huberland F, Vanhoestenberghe A, Lambert P, Acuña V, Smets H, Giannotta F, Delchambre A, Sandersen C, Bolen G, Egyptien S, Deleuze S, Devière J, Nonclercq A. Optimization and assessment of a novel gastric electrode anchoring system designed to be implanted by minimally invasive surgery. Med Eng Phys 2021; 92:93-101. [PMID: 34167717 DOI: 10.1016/j.medengphy.2021.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 04/27/2021] [Accepted: 05/05/2021] [Indexed: 11/16/2022]
Abstract
A novel electrode anchoring design and its implantation procedure, aiming for a minimally invasive solution for gastric electrical stimulation, are presented. The system comprises an anchor made of a flexible body embedding two needle-shaped electrodes. The electrodes can easily switch from a parallel position - to pierce the stomach - to a diverging position - enabling them to remain firmly anchored into the muscular layer of the stomach. Key device parameters governing anchoring stability were assessed on a traction test bench, and optimal values were derived. The device was then implanted in six dogs by open surgery to assess its anchoring durability in vivo. Computed tomography images showed that the electrodes remained well placed within the dogs' gastric wall over the entire assessment period (more than one year). Finally, a prototype of a surgical tool for the minimally invasive device placement was manufactured, and the anchoring procedure was tested on a dog cadaver, providing the proof of concept of the minimally invasive implantation procedure. The use of our electrode anchoring system in long-term gastric electrical stimulation is promising in terms of implantation stability (the anchor withstands a force up to 0.81 N), durability (the anchor remains onto the stomach over one year) and minimal invasiveness of the procedure (the diameter of the percutaneous access is smaller than 12 mm). Moreover, the proposed design could have clinical applications in other hollow organs, such as the urinary bladder.
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Affiliation(s)
- Adrien Debelle
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium.
| | - Hilde de Rooster
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Erika Bianchini
- Small Animal Department, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Laurent Lonys
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - François Huberland
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, Department of Materials and Tissue, University College London, Stanmore, United Kingdom
| | - Pierre Lambert
- Transfers, Interfaces and Processes Department (TIPS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Vicente Acuña
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Hugo Smets
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Fabrizio Giannotta
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Alain Delchambre
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Charlotte Sandersen
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Geraldine Bolen
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Sophie Egyptien
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Stefan Deleuze
- Fundamental and Applied Research for Animal & Health (FARAH), Department of Clinical Sciences, Faculty of Veterinary Medicine, University of Liege, Liege, Belgium
| | - Jacques Devière
- Department of Gastroenterology, Hepatopancreatology, and Digestive Oncology, Erasmus University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems Department (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
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23
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Cury J, Vande Perre L, Smets H, Stumpp L, Vespa S, Vanhoestenberghe A, Doguet P, Delbeke J, El Tahry R, Gorza SP, Nonclercq A. Infrared neurostimulation in ex-vivorat sciatic nerve using 1470 nm wavelength. J Neural Eng 2021; 18. [PMID: 33770780 DOI: 10.1088/1741-2552/abf28f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 03/26/2021] [Indexed: 12/22/2022]
Abstract
Objective.To design and implement a setup forex-vivooptical stimulation for exploring the effect of several key parameters (optical power and pulse duration), activation features (threshold, spatial selectivity) and recovery characteristics (repeated stimuli) in peripheral nerves.Approach.A nerve chamber allowing ex-vivo electrical and optical stimulation was designed and built. A 1470 nm light source was chosen to stimulate the nerve. A photodiode module was implemented for synchronization of the electrical and optical channels.Main results. Compound neural action potentials (CNAPs) were successfully generated with infrared light pulses of 200-2000µs duration and power in the range of 3-10 W. These parameters determine a radiant exposure for stimulation in the range 1.59-4.78 J cm-2. Recruitment curves were obtained by increasing durations at a constant power level. Neural activation threshold is reached at a mean radiant exposure of 3.16 ± 0.68 J cm-2and mean pulse energy of 3.79 ± 0.72 mJ. Repetition rates of 2-10 Hz have been explored. In eight out of ten sciatic nerves (SNs), repeated light stimuli induced a sensitization effect in that the CNAP amplitude progressively grows, representing an increasing number of recruited fibres. In two out of ten SNs, CNAPs were composed of a succession of peaks corresponding to different conduction velocities.Significance.The reported sensitization effect could shed light on the mechanism underlying infrared neurostimulation. Our results suggest that, in sharp contrast with electrical stimuli, optical pulses could recruit slow fibres early on. This more physiological order of recruitment opens the perspective for specific neuromodulation of fibre population who remained poorly accessible until now. Short high-power light pulses at wavelengths below 1.5µm offer interesting perspectives for neurostimulation.
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Affiliation(s)
- Joaquin Cury
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium.,Opera Photonics, Université libre de Bruxelles, Brussels, Belgium
| | - Louis Vande Perre
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
| | - Hugo Smets
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
| | - Lars Stumpp
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | - Simone Vespa
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, University College London, London, United Kingdom
| | | | - Jean Delbeke
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | - Riëm El Tahry
- Institute of Neurosciences (IONS), Université Catholique de Louvain, Belgium-Cliniques Universitaires Saint Luc, Department of Neurology, Brussels, Belgium
| | | | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems (BEAMS), Université libre de Bruxelles, Brussels, Belgium
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Smets H, Stumpp L, Julémont N, Cury J, Debelle A, Innocenti B, Vespa S, Haut B, Doguet P, Vanhoestenberghe A, Delbeke J, El Tahry R, Nonclercq A. Analysing vagus nerve spontaneous activity using finite element modelling. J Neural Eng 2021; 18. [PMID: 33588393 DOI: 10.1088/1741-2552/abe68f] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 02/15/2021] [Indexed: 11/11/2022]
Abstract
OBJECTIVE Finite element modelling has been widely used to understand the effect of stimulation on the nerve fibres. Yet the literature on analysis of spontaneous nerve activity is much scarcer. In this study, we introduce a method based on a finite element model, to analyse spontaneous nerve activity with a typical bipolar electrode recording setup, enabling the identification of spontaneously active fibres. We applied our method to the vagus nerve, which plays a key role in refractory epilepsy. APPROACH We developed a 3D model including dynamic action potential propagation, based on the vagus nerve geometry. The impact of key recording parameters - inter-electrode distance and temperature - and uncontrolled parameters - fibre size and position in the nerve - on the ability to discriminate active fibres were quantified. A specific algorithm was implemented to detect and classify action potentials from recordings and tested on six rats in vivo vagus nerve recordings. MAIN RESULTS Fibre diameters can be discriminated if they are below 3 µm and 7 µm, respectively for inter-electrode distances of 2 mm and 4 mm. The impact of the position of the fibre inside the nerve on fibre diameter discrimination, is limited. The range of active fibres identified by modelling in the vagus nerve of rats is in agreement with ranges found at histology. SIGNIFICANCE The nerve fibre diameter, directly proportional to the action potential propagation velocity, is related to a specific physiological function. Estimating the source fibre diameter is thus essential to interpret neural recordings. Among many possible applications, the present method was developed in the context of a project to improve vagus nerve stimulation therapy for epilepsy.
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Affiliation(s)
- Hugo Smets
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Brussels, 1050, BELGIUM
| | - Lars Stumpp
- IONS, Université catholique de Louvain, Avenue Mounier 53/B1.53.05, Brussels, 1200, BELGIUM
| | - Nicolas Julémont
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt 50 CP 165/56, Brussels, 1050, BELGIUM
| | - Joaquin Cury
- Bio, Electro and Mechanical Systems (BEAMS), Université Libre de Bruxelles, Avenue Franklin Roosevelt 50 CP 165/56, Brussels, 1050, BELGIUM
| | - Adrien Debelle
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt 50 CP 165/56, Brussels, 1050, BELGIUM
| | - Bernardo Innocenti
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt 50 CP 165/56, Brussels, 1050, BELGIUM
| | - Simone Vespa
- IONS, Université catholique de Louvain, Avenue Mounier 53/B1.53.05, Brussels, 1200, BELGIUM
| | - Benoit Haut
- TIPs, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt 50 CP 165/67, Brussels, 1050, BELGIUM
| | - Pascal Doguet
- Synergia Medical SA, Rue Emile Francqui, 6, Mont-Saint-Guibert, 1435, BELGIUM
| | - Anne Vanhoestenberghe
- Implanted Devices Group, University College London, Aspire Create - IOMS BUilding, RNOH campus, Brockley Hill, London, HA74LP, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND
| | - Jean Delbeke
- Private Address - Belgium, Seringenstraat 27, Kraainem, B-1950, BELGIUM
| | - Riëm El Tahry
- IONS, Université catholique de Louvain, Avenue Mounier 53/B1.53.05, Brussels, 1200, BELGIUM
| | - Antoine Nonclercq
- BEAMS, Université Libre de Bruxelles Faculté des sciences appliquées/Ecole polytechnique, Avenue Franklin Roosevelt, 50, CP 165/56, Bruxelles, 1050, BELGIUM
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Hossein A, Rabineau J, Gorlier D, Del Rio JIJ, van de Borne P, Migeotte PF, Nonclercq A. Kinocardiography Derived from Ballistocardiography and Seismocardiography Shows High Repeatability in Healthy Subjects. Sensors (Basel) 2021; 21:815. [PMID: 33530417 PMCID: PMC7865512 DOI: 10.3390/s21030815] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/20/2021] [Accepted: 01/21/2021] [Indexed: 01/14/2023]
Abstract
Recent years have witnessed an upsurge in the usage of ballistocardiography (BCG) and seismocardiography (SCG) to record myocardial function both in normal and pathological populations. Kinocardiography (KCG) combines these techniques by measuring 12 degrees-of-freedom of body motion produced by myocardial contraction and blood flow through the cardiac chambers and major vessels. The integral of kinetic energy (iK) obtained from the linear and rotational SCG/BCG signals, and automatically computed over the cardiac cycle, is used as a marker of cardiac mechanical function. The present work systematically evaluated the test-retest (TRT) reliability of KCG iK derived from BCG/SCG signals in the short term (<15 min) and long term (3-6 h) on 60 healthy volunteers. Additionally, we investigated the difference of repeatability with different body positions. First, we found high short-term TRT reliability for KCG metrics derived from SCG and BCG recordings. Exceptions to this finding were limited to metrics computed in left lateral decubitus position where the TRT reliability was moderate-to-high. Second, we found low-to-moderate long-term TRT reliability for KCG metrics as expected and confirmed by blood pressure measurements. In summary, KCG parameters derived from BCG/SCG signals show high repeatability and should be further investigated to confirm their use for cardiac condition longitudinal monitoring.
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Affiliation(s)
- Amin Hossein
- LPHYS, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (J.R.); (D.G.); (P.-F.M.)
- BEAMS, Université Libre de Bruxelles, 1050 Bruxelles, Belgium;
| | - Jérémy Rabineau
- LPHYS, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (J.R.); (D.G.); (P.-F.M.)
| | - Damien Gorlier
- LPHYS, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (J.R.); (D.G.); (P.-F.M.)
| | - Jose Ignacio Juarez Del Rio
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (J.I.J.D.R.); (P.v.d.B.)
| | - Philippe van de Borne
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, 1050 Bruxelles, Belgium; (J.I.J.D.R.); (P.v.d.B.)
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Hossein A, Rabineau J, Gorlier D, Pinki F, van de Borne P, Nonclercq A, Migeotte PF. Effects of acquisition device, sampling rate, and record length on kinocardiography during position-induced haemodynamic changes. Biomed Eng Online 2021; 20:3. [PMID: 33407507 PMCID: PMC7788803 DOI: 10.1186/s12938-020-00837-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/10/2020] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Kinocardiography (KCG) is a promising new technique used to monitor cardiac mechanical function remotely. KCG is based on ballistocardiography (BCG) and seismocardiography (SCG), and measures 12 degrees-of-freedom (DOF) of body motion produced by myocardial contraction and blood flow through the cardiac chambers and major vessels. RESULTS The integral of kinetic energy ([Formula: see text]) obtained from the linear and rotational SCG/BCG signals was computed over each dimension over the cardiac cycle, and used as a marker of cardiac mechanical function. We tested the hypotheses that KCG metrics can be acquired using different sensors, and at 50 Hz. We also tested the effect of record length on the ensemble average on which the metrics were computed. Twelve healthy males were tested in the supine, head-down tilt, and head-up tilt positions to expand the haemodynamic states on which the validation was performed. CONCLUSIONS KCG metrics computed on 50 Hz and 1 kHz SCG/BCG signals were very similar. Most of the metrics were highly similar when computed on different sensors, and with less than 5% of error when computed on record length longer than 60 s. These results suggest that KCG may be a robust and non-invasive method to monitor cardiac inotropic activity. Trial registration Clinicaltrials.gov, NCT03107351. Registered 11 April 2017, https://clinicaltrials.gov/ct2/show/NCT03107351?term=NCT03107351&draw=2&rank=1 .
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Affiliation(s)
- Amin Hossein
- LPHYS, Université Libre de Bruxelles, Brussels, Belgium.
- BEAMS, Université Libre de Bruxelles, Brussels, Belgium.
| | | | | | - Farhana Pinki
- LPHYS, Université Libre de Bruxelles, Brussels, Belgium
| | - Philippe van de Borne
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Brussels, Belgium
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Lucchetti F, Nonclercq A, Avan P, Giraudet F, Fan X, Deltenre P. Subcortical neural generators of the envelope-following response in sleeping children: A transfer function analysis. Hear Res 2020; 401:108157. [PMID: 33360182 DOI: 10.1016/j.heares.2020.108157] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 12/10/2020] [Accepted: 12/14/2020] [Indexed: 01/23/2023]
Abstract
Multiple auditory structures, from cochlea to cortex, phase-lock to the envelope of complex stimuli. The relative contributions of these structures to the human surface-recorded envelope-following response (EFR) are still uncertain. Identification of the active contributor(s) is complicated by the fact that even the simplest two-tone (f1&f2) stimulus, targeting its (f2-f1) envelope, evokes additional linear (f1&f2) and non-linear (2f1-f2) phase-locked components as well as a transient auditory brainstem response (ABR). Here, we took advantage of the generalized primary tone phase variation method to isolate each predictable component in the time domain, allowing direct measurements of onset latency, duration and phase discontinuity values from which the involved generators were inferred. Targeting several envelope frequencies (0.22-1 kHz), we derived the EFR transfer functions along a vertical vertex-to-neck and a horizontal earlobe-to-earlobe recording channels, yielding respectively EFR-V and EFR-H waveforms. Subjects (N= 30) were sleeping children with normal electrophysiological thresholds and normal oto-acoustic emissions. Both EFR-H and EFR-V phase-locking values (PLV) transfer functions had a low-pass profile, EFR-V showing a lower cut-off frequency than EFR-H. We also computed the frequency-latency relationships of both EFRs onset latencies. EFR-H data fitted a power-law function incorporating a frequency-dependent traveling wave delay and a fixed one amounting to 1.2 ms. The fitted function nicely fell within five published estimations of the latency-frequency function of the ABR wave-I, thus pointing to a cochlear nerve origin. The absence of phase discontinuity and overall response durations that were equal to that of the stimulus indicated no contribution from a later generator. The recording of an entirely similar EFR-H response in a patient who had severe brainstem encephalitis with a normal, isolated, ABR wave-I but complete absence of later waves, further substantiated a cochlear nerve origin. Modeling of the EFR-V latency-frequency functions indicated a fixed transport time of 2 ms with respect to EFR-H onset, suggesting a cochlear nucleus (CN) origin, here also, without indication for multiple generators. Other features of the EFR-V response pointing to the CN were, at least for the EFR frequency below the cut-off values of the transfer functions, higher PLVs coupled with increased harmonic distortion. Such a behavior has been described in the so-called highly-synchronized neurons of the ventral cochlear nucleus (VCN). The present study compellingly demonstrated the advantage of isolating the EFR in the temporal domain so as to extract detailed spectro-temporal parameters that, combined with orthogonal recording channels, shed new light on the involved neural generators.
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Affiliation(s)
- Federico Lucchetti
- Bio-, Electro- and Mechanical Systems, CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, Brussels 1050, Belgium; Laboratoire de Neurophysiologie Sensorielle et Cognitive, CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels 1020, Belgium.
| | - Antoine Nonclercq
- Bio-, Electro- and Mechanical Systems, CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, Brussels 1050, Belgium; Laboratoire de Neurophysiologie Sensorielle et Cognitive, CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels 1020, Belgium; Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale, University Clermont Auvergne, 28 Place Henri Dunant, BP38, Clermont-Ferrand F63001, France.
| | - Paul Avan
- Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale, University Clermont Auvergne, 28 Place Henri Dunant, BP38, Clermont-Ferrand F63001, France.
| | - Fabrice Giraudet
- Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale, University Clermont Auvergne, 28 Place Henri Dunant, BP38, Clermont-Ferrand F63001, France.
| | - Xiaoya Fan
- Bio-, Electro- and Mechanical Systems, CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50, Brussels 1050, Belgium.
| | - Paul Deltenre
- Laboratoire de Neurophysiologie Sensorielle et Cognitive, CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels 1020, Belgium.
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Buess A, Van Muylem A, Nonclercq A, Haut B. Modeling of the Transport and Exchange of a Gas Species in Lungs With an Asymmetric Branching Pattern. Application to Nitric Oxide. Front Physiol 2020; 11:570015. [PMID: 33362572 PMCID: PMC7758446 DOI: 10.3389/fphys.2020.570015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/21/2020] [Indexed: 01/25/2023] Open
Abstract
Over the years, various studies have been dedicated to the mathematical modeling of gas transport and exchange in the lungs. Indeed, the access to the distal region of the lungs with direct measurements is limited and, therefore, models are valuable tools to interpret clinical data and to give more insights into the phenomena taking place in the deepest part of the lungs. In this work, a new computational model of the transport and exchange of a gas species in the human lungs is proposed. It includes (i) a method to generate a lung geometry characterized by an asymmetric branching pattern, based on the values of several parameters that have to be given by the model user, and a method to possibly alter this geometry to mimic lung diseases, (ii) the calculation of the gas flow distribution in this geometry during inspiration or expiration (taking into account the increased resistance to the flow in airways where the flow is non-established), (iii) the evaluation of the exchange fluxes of the gaseous species of interest between the tissues composing the lungs and the lumen, and (iv) the computation of the concentration profile of the exchanged species in the lumen of the tracheobronchial tree. Even if the model is developed in a general framework, a particular attention is given to nitric oxide, as it is not only a gas species of clinical interest, but also a gas species that is both produced in the walls of the airways and consumed within the alveolar region of the lungs. First, the model is presented. Then, several features of the model, applied to lung geometry, gas flow and NO exchange and transport, are discussed, compared to existing works and notably used to give new insights into experimental data available in the literature, regarding diseases, such as asthma, cystic fibrosis, and chronic obstructive pulmonary disease.
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Affiliation(s)
- Alexandra Buess
- Transfers, Interfaces and Processes, Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Alain Van Muylem
- Chest Department, Erasme University Hospital, Université Libre de Bruxelles, Brussels, Belgium
| | - Antoine Nonclercq
- Bio-, Electro-, and Mechanical Systems (BEAMS), Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
| | - Benoit Haut
- Transfers, Interfaces and Processes, Ecole Polytechnique de Bruxelles, Université Libre de Bruxelles, Brussels, Belgium
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Stumpp L, Smets H, Vespa S, Cury J, Doguet P, Delbeke J, Hermans E, Sevcencu C, Nielsen TN, Nonclercq A, Tahry RE. Recording of spontaneous vagus nerve activity during Pentylenetetrazol-induced seizures in rats. J Neurosci Methods 2020; 343:108832. [DOI: 10.1016/j.jneumeth.2020.108832] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/08/2020] [Accepted: 06/24/2020] [Indexed: 01/23/2023]
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Bastin O, Thulliez M, Servais J, Nonclercq A, Delchambre A, Hadefi A, Devière J, Reniers F. Optical and Electrical Characteristics of an Endoscopic DBD Plasma Jet. Plasma Med 2020. [DOI: 10.1615/plasmamed.2020034526] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Vespa S, Stumpp L, Bouckaert C, Delbeke J, Smets H, Cury J, Ferrao Santos S, Rooijakkers H, Nonclercq A, Raedt R, Vonck K, El Tahry R. Vagus Nerve Stimulation-Induced Laryngeal Motor Evoked Potentials: A Possible Biomarker of Effective Nerve Activation. Front Neurosci 2019; 13:880. [PMID: 31507360 PMCID: PMC6718640 DOI: 10.3389/fnins.2019.00880] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 08/05/2019] [Indexed: 11/13/2022] Open
Abstract
Vagus nerve stimulation (VNS) therapy is associated with laryngeal muscle activation and induces voice modifications, well-known side effects of the therapy resulting from co-activation of the recurrent laryngeal nerve. In this study, we describe the non-invasive transcutaneous recording of laryngeal motor evoked potentials (LMEPs), which could serve as a biomarker of effective nerve activation and individual titration in patients with drug-resistant epilepsy. We recruited drug-resistant epileptic patients treated for at least 6 months with a VNS. Trains of 600-1200 VNS pulses were delivered with increasing current outputs. We placed six skin electrodes on the ventral surface of the neck, in order to record LMEPs whenever the laryngeal muscular threshold was reached. We studied the internal consistency and the variability of LMEP recordings, and compared different methods for amplitude calculation. Recruitment curves were built based on the stimulus-response relationship. We also determined the electrical axis of the LMEPs dipole in order to define the optimal electrode placement for LMEPs recording in a clinical setting. LMEPs were successfully recorded in 11/11 patients. The LMEPs threshold ranged from 0.25 to 1 mA (median 0.50 mA), and onset latency was between 5.37 and 8.77 ms. The signal-to-noise ratio was outstanding in 10/11 patients. In these cases, excellent reliability (Intraclass correlation coefficient, ICC > 0.90 across three different amplitude measurements) was achieved with 10 sample averages. Moreover, our recordings showed very good internal consistency (Cronbach's alpha > 0.95 for 10 epochs). Area-under-the-curve and peak-to-peak measurement proved to be complementary methods for amplitude calculation. Finally, we determined that an optimal derivation requires only two recording electrodes, aligned on a horizontal axis around the laryngeal prominence. In conclusion, we describe here an optimal methodology for the recording of VNS-induced motor evoked responses from the larynx. Although further clinical validation is still necessary, LMEPs might be useful as a non-invasive marker of effective nerve activation, and as an aid for the clinician to perform a more rational titration of VNS parameters.
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Affiliation(s)
- Simone Vespa
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Lars Stumpp
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | | | - Jean Delbeke
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium
| | - Hugo Smets
- Bio, Electro And Mechanical Systems, Université Libre de Bruxelles, Brussels, Belgium
| | - Joaquin Cury
- Bio, Electro And Mechanical Systems, Université Libre de Bruxelles, Brussels, Belgium
| | - Susana Ferrao Santos
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.,Centre for Refractory Epilepsy, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Herbert Rooijakkers
- Department of Neurosurgery, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro And Mechanical Systems, Université Libre de Bruxelles, Brussels, Belgium
| | - Robrecht Raedt
- 4Brain, Institute for Neurosciences, Ghent University, Ghent, Belgium
| | - Kristl Vonck
- 4Brain, Institute for Neurosciences, Ghent University, Ghent, Belgium.,Reference Center for Refractory Epilepsy, Department of Neurology, Ghent University, Ghent, Belgium
| | - Riëm El Tahry
- Institute of Neuroscience, Université catholique de Louvain, Brussels, Belgium.,Centre for Refractory Epilepsy, Cliniques Universitaires Saint-Luc, Brussels, Belgium
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Hossein A, Mirica DC, Rabineau J, Rio JID, Morra S, Gorlier D, Nonclercq A, van de Borne P, Migeotte PF. Accurate Detection of Dobutamine-induced Haemodynamic Changes by Kino-Cardiography: A Randomised Double-Blind Placebo-Controlled Validation Study. Sci Rep 2019; 9:10479. [PMID: 31324831 PMCID: PMC6642180 DOI: 10.1038/s41598-019-46823-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 07/01/2019] [Indexed: 01/26/2023] Open
Abstract
Non-invasive remote detection of cardiac and blood displacements is an important topic in cardiac telemedicine. Here we propose kino-cardiography (KCG), a non-invasive technique based on measurement of body vibrations produced by myocardial contraction and blood flow through the cardiac chambers and major vessels. KCG is based on ballistocardiography and measures 12 degrees-of-freedom (DOF) of body motion. We tested the hypothesis that KCG reliably assesses dobutamine-induced haemodynamic changes in healthy subjects. Using a randomized double-blinded placebo-controlled crossover study design, dobutamine and placebo were infused to 34 volunteers (25 ± 2 years, BMI 22 ± 2 kg/m², 18 females). Baseline recordings were followed by 3 sessions of increasing doses of dobutamine (5, 10, 20 μg/kg.min) or saline solution. During each session, stroke volume (SV) and cardiac output (CO) were determined by echocardiography and followed by a 90 s KCG recording. Measured linear accelerations and angular velocities were used to compute total Kinetic energy (iK) and power (Pmax). KCG sorted dobutamine infusion vs. placebo with 96.9% accuracy. Increases in SV and CO were correlated to iK (r = +0.71 and r = +0.8, respectively, p < 0.0001). Kino-cardiography, with 12-DOF, allows detecting dobutamine-induced haemodynamic changes with a high accuracy and present a major improvement over single axis ballistocardiography or seismocardiography.
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Affiliation(s)
- Amin Hossein
- LPHYS, Université Libre de Bruxelles, Bruxelles, Belgium.
- BEAMS, Université Libre de Bruxelles, Bruxelles, Belgium.
| | - Daniela Corina Mirica
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Bruxelles, Belgium
| | | | - José Ignacio Del Rio
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Sofia Morra
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Damien Gorlier
- LPHYS, Université Libre de Bruxelles, Bruxelles, Belgium
| | | | - Philippe van de Borne
- Department of Cardiology, Erasme Hospital, Université Libre de Bruxelles, Bruxelles, Belgium
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Lucchetti F, Deltenre P, Avan P, Giraudet F, Fan X, Nonclercq A. Generalization of the primary tone phase variation method: An exclusive way of isolating the frequency-following response components. J Acoust Soc Am 2018; 144:2400. [PMID: 30404467 DOI: 10.1121/1.5063821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
The primary tone phase variation (PTPV) technique combines selective sub-averaging with systematic variation of the phases of multitone stimuli. Each response component having a known phase relationship with the stimulus components phases can be isolated in the time domain. The method was generalized to the frequency-following response (FFR) evoked by a two-tone (f 1 and f 2) stimulus comprising both linear and non-linear, as well as transient components. The generalized PTPV technique isolated each spectral component present in the FFR, including those sharing the same frequency, allowing comparison of their latencies. After isolation of the envelope component f 2 - f 1 from its harmonic distortion 2f 2 - 2f 1 and from the transient auditory brainstem response, a computerized analysis of instantaneous amplitudes and phases was applied in order to objectively determine the onset and offset latencies of the response components. The successive activation of two generators separated by 3.7 ms could be detected in all (N = 12) awake adult normal subjects, but in none (N = 10) of the sleeping/sedated children with normal hearing thresholds. The method offers an unprecedented way of disentangling the various FFR subcomponents. These results open the way for renewed investigations of the FFR components in both human and animal research as well as for clinical applications.
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Affiliation(s)
- Federico Lucchetti
- Laboratoire de Neurophysiologie Sensorielle et Cognitive CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels, B1060, Belgium
| | - Paul Deltenre
- Laboratoire de Neurophysiologie Sensorielle et Cognitive CP403/22, Brugmann Hospital, Place Van Gehuchten 4, Brussels, B1060, Belgium
| | - Paul Avan
- Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale 1107, University Clermont Auvergne, 28 Place Henri Dunant, BP38 Clermont-Ferrand, Cedex 1, F63001, France
| | - Fabrice Giraudet
- Laboratory of Neurosensory Biophysics Unité mixte de recherche, Institut national de la santé et de la recherche médicale 1107, University Clermont Auvergne, 28 Place Henri Dunant, BP38 Clermont-Ferrand, Cedex 1, F63001, France
| | - Xiaoya Fan
- Bio-, Electro- and Mechanical Systems CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50 Brussels, B1050, Belgium
| | - Antoine Nonclercq
- Bio-, Electro- and Mechanical Systems CP165/56, Université Libre de Bruxelles, Avenue F. D. Roosevelt, 50 Brussels, B1050, Belgium
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Fan X, Gaspard N, Legros B, Lucchetti F, Ercek R, Nonclercq A. Seizure evolution can be characterized as path through synaptic gain space of a neural mass model. Eur J Neurosci 2018; 48:3097-3112. [PMID: 30194874 DOI: 10.1111/ejn.14142] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/08/2018] [Accepted: 08/29/2018] [Indexed: 11/30/2022]
Abstract
Physiologically based models could facilitate better understanding of mechanisms underlying epileptic seizures. In this paper, we attempt to reveal the dynamic evolution of intracranial EEG activity during epileptic seizures based on synaptic gain identification procedure of a neural mass model. The distribution of average excitatory, slow and fast inhibitory synaptic gain in the parameter space and their temporal evolution, i.e., the path through the model parameter space, were analyzed in thirty seizures from ten temporal lobe epileptic patients. Results showed that the synaptic gain values located roughly on a plane before seizure onset, dispersed during seizure and returned to the plane when seizure terminated. Cluster analysis was performed on seizure paths and demonstrated consistency in synaptic gain evolution across different seizures from the individual patient. Furthermore, two patient groups were identified, each one corresponding to a specific synaptic gain evolution in the parameter space during a seizure. Results were validated by a bootstrapping approach based on comparison with random paths. The differences in the path revealed variations in EEG dynamics for patients despite showing identical seizure onset pattern. Our approach may have the potential to classify the epileptic patients into subgroups based on different mechanisms revealed by subtle changes in synaptic gains and further enable more robust decisions regarding treatment strategy.
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Affiliation(s)
- Xiaoya Fan
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Benjamin Legros
- Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Federico Lucchetti
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Brussels, Belgium.,Laboratoire de Neurophysiologie Sensorielle et Cognitive, Hôpital Brugmann, Brussels, Belgium
| | - Rudy Ercek
- Laboratories of Image, Signal Processing and Acoustics (LISA), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Brussels, Belgium
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Lonys L, Vanhoestenberghe A, Huberty V, Hiernaux M, Cauche N, Julémont N, Debelle A, Huberland F, Acuña V, Godfraind C, Devière J, Delchambre A, Mathys P, Deleuze S, Nonclercq A. In Vivo Validation of a Less Invasive Gastrostimulator. Artif Organs 2018; 41:E213-E221. [PMID: 29148134 DOI: 10.1111/aor.13056] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Gastrointestinal stimulator implants have recently shown promising results in helping obese patients lose weight. However, to place the implant, the patient currently needs to undergo an invasive surgical procedure. We report a less invasive procedure to stimulate the stomach with a gastrostimulator. After attempting fully endoscopic implantation, we more recently focused on a single incision percutaneous procedure. In both cases, the challenges in electronic design of the implant are largely similar. This article covers the work achieved to meet these and details the in vivo validation of a gastrostimulator aimed to be endoscopically placed and anchored to the stomach.
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Affiliation(s)
- Laurent Lonys
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology, Department of Materials and Tissue, University College London, Stanmore, United Kingdom
| | - Vincent Huberty
- Department of Gastroenterology, Hepatopancreatology, and Digestive Oncology, Université Libre de Bruxelles, Erasme University Hospital, Brussels, Belgium
| | | | - Nicolas Cauche
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Nicolas Julémont
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Adrien Debelle
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - François Huberland
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Vicente Acuña
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Carmen Godfraind
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Jacques Devière
- Department of Gastroenterology, Hepatopancreatology, and Digestive Oncology, Université Libre de Bruxelles, Erasme University Hospital, Brussels, Belgium
| | - Alain Delchambre
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Pierre Mathys
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
| | - Stefan Deleuze
- Départment des Sciences Cliniques-Clinique Equine, Université de Liège, Liège, Belgium
| | - Antoine Nonclercq
- Bio, Electro and Mechanical Systems Department, Université Libre de Bruxelles, Brussels, Belgium
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Fan X, Gaspard N, Legros B, Lucchetti F, Ercek R, Nonclercq A. Dynamics underlying interictal to ictal transition in temporal lobe epilepsy: insights from a neural mass model. Eur J Neurosci 2018; 47:258-268. [PMID: 29282779 DOI: 10.1111/ejn.13812] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 11/27/2017] [Accepted: 12/18/2017] [Indexed: 12/15/2022]
Abstract
We propose an approach that combines a neural mass model and clinical intracranial electroencephalographic (iEEG) recordings to explore the potential pathophysiological mechanisms (at the neuronal population level) of ictogenesis. Thirty iEEG recordings from 10 temporal lobe epilepsy (TLE) patients around seizure onset were investigated. Physiologically meaningful parameters [average excitatory (Ae ), slow (B), and fast (G) inhibitory synaptic gain] were identified during interictal to ictal transition. Four ratios (Ae /G, Ae /B, Ae /(B + G), and B/G) were derived from these parameters, and their evolution over time was analyzed. The excitation/inhibition ratio increased around seizure onset and decreased before seizure offset, indicating the impairment and re-emergence of excitation/inhibition balance around seizure onset and before seizure offset, respectively. Moreover, the slow inhibition may have an earlier effect on excitation/inhibition imbalance. We confirm the decrease in excitation/inhibition ratio upon seizure termination in human temporal lobe epilepsy, as revealed by optogenetic approaches both in vivo in animal models and in vitro. The increase in excitation/inhibition ratio around seizure occurrence could be an indicator to detect seizures.
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Affiliation(s)
- Xiaoya Fan
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium
| | - Nicolas Gaspard
- Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Benjamin Legros
- Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Federico Lucchetti
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium.,Laboratoire de Neurophysiologie Sensorielle et Cognitive, Hôpital Brugmann, Brussels, Belgium
| | - Rudy Ercek
- Laboratories of Image, Signal processing and Acoustics (LISA), Université Libre de Bruxelles (ULB), Brussels, Belgium
| | - Antoine Nonclercq
- Bio, Electro And Mechanical Systems (BEAMS), Université Libre de Bruxelles (ULB), Avenue F.D. Roosevelt 50 CP165/56, 1050, Brussels, Belgium
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Mouraux D, Brassinne E, Sobczak S, Nonclercq A, Warzée N, Sizer PS, Tuna T, Penelle B. 3D augmented reality mirror visual feedback therapy applied to the treatment of persistent, unilateral upper extremity neuropathic pain: a preliminary study. J Man Manip Ther 2017; 25:137-143. [PMID: 28694676 DOI: 10.1080/10669817.2016.1176726] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Objective: We assessed whether or not pain relief could be achieved with a new system that combines 3D augmented reality system (3DARS) and the principles of mirror visual feedback. Methods: Twenty-two patients between 18 and 75 years of age who suffered of chronic neuropathic pain. Each patient performed five 3DARS sessions treatment of 20 mins spread over a period of one week. The following pain parameters were assessed: (1) visual analogic scale after each treatment session (2) McGill pain scale and DN4 questionnaire were completed before the first session and 24 h after the last session. Results: The mean improvement of VAS per session was 29% (p < 0.001). There was an immediate session effect demonstrating a systematic improvement in pain between the beginning and the end of each session. We noted that this pain reduction was partially preserved until the next session. If we compare the pain level at baseline and 24 h after the last session, there was a significant decrease (p < 0.001) of pain of 37%. There was a significant decrease (p < 0.001) on the McGill Pain Questionnaire and DN4 questionnaire (p < 0.01). Conclusion: Our results indicate that 3DARS induced a significant pain decrease for patients who presented chronic neuropathic pain in a unilateral upper extremity. While further research is necessary before definitive conclusions can be drawn, clinicians could implement the approach as a preparatory adjunct for providing temporary pain relief aimed at enhancing chronic pain patients' tolerance of manual therapy and exercise intervention. Level of Evidence: 4.
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Affiliation(s)
- Dominique Mouraux
- Department of Physical Therapy and Rehabilitation, Hôpital Erasme, Université libre de Bruxelles, ULB, Bruxelles, Belgium
| | - Eric Brassinne
- Department of Physical Therapy and Rehabilitation, Hôpital Erasme, Université libre de Bruxelles, ULB, Bruxelles, Belgium
| | - Stéphane Sobczak
- Department of Physical Therapy and Rehabilitation, Hôpital Erasme, Université libre de Bruxelles, ULB, Bruxelles, Belgium.,Département d'anatomie, Université du Québec à Trois-Rivières, Trois-Rivières, QC, Canada.,Department of Rehabilitation Sciences, Center for Rehabilitation Research, School of Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Antoine Nonclercq
- Belgium BEAMS Department - Bio, Electro and Mechanical Systems, Université libre de Bruxelles, ULB, Bruxelles, Belgium
| | - Nadine Warzée
- LISA Laboratory, Université libre de Bruxelles, ULB, Bruxelles, Belgium
| | - Phillip S Sizer
- Department of Rehabilitation Sciences, Center for Rehabilitation Research, School of Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Turgay Tuna
- Department of Anaesthesiology, Pain Clinic, Hôpital Erasme, Université libre de Bruxelles, ULB, Bruxelles, Belgium
| | - Benoît Penelle
- LISA Laboratory, Université libre de Bruxelles, ULB, Bruxelles, Belgium
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Debelle A, Hermans L, Bosquet M, Dehaeck S, Lonys L, Scheid B, Nonclercq A, Vanhoestenberghe A. Soft Encapsulation of Flexible Electrical Stimulation Implant: Challenges and Innovations. Eur J Transl Myol 2016; 26:6298. [PMID: 28078073 PMCID: PMC5220220 DOI: 10.4081/ejtm.2016.6298] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this document we discuss the main challenges encountered when producing flexible electrical stimulation implants, and present our approach to solving them for prototype production. We include a study of the optimization of the flexible PCB design, the selection of additive manufacturing materials for the mold, and the chemical compatibility of the different materials. Our approach was tested on a flexible gastro-stimulator as part of the ENDOGES research program.
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Affiliation(s)
- Adrien Debelle
- Ecole Polytechnique de Bruxelles, at the Université Libre de Bruxelles
| | - Laura Hermans
- Ecole Polytechnique de Bruxelles, at the Université Libre de Bruxelles
| | - Maxime Bosquet
- E.C.A.M., at the Haute Ecole Léonard de Vinci , Brussels, Belgium
| | - Sam Dehaeck
- Ecole Polytechnique de Bruxelles, at the Université Libre de Bruxelles
| | - Laurent Lonys
- Ecole Polytechnique de Bruxelles, at the Université Libre de Bruxelles
| | - Benoit Scheid
- Ecole Polytechnique de Bruxelles, at the Université Libre de Bruxelles
| | - Antoine Nonclercq
- Ecole Polytechnique de Bruxelles, at the Université Libre de Bruxelles
| | - Anne Vanhoestenberghe
- Aspire Centre for Rehabilitation Engineering and Assistive Technology at University College London
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Abstract
Cross-talk phenomena should be avoided when stimulating nerves. One option to limit the current spread is to use tripolar electrodes, but at the cost of increasing the number of wires connection. This should be avoided since cables must be thin and compliant. We investigated the impact of the central electrode position and of current spread due to a gap between book and lid on cross-talk, in a set of tripolar or quasi-tripolar configurations..
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Abstract
Photonic stimulation is a new modality of nerve stimulation, which could overcome some of the electrical stimulation limitations. In this paper, we present the results of photonic stimulation of rodent sciatic nerve with a 1470 nm laser. Muscle activation was observed with radiant exposure of 0.084 J/cm².
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Affiliation(s)
- Marie Dautrebande
- Synergia Medical, Mont-Saint-Guibert, Belgium; Université libre de Bruxelles, Brussels, Belgium
| | | | | | - Jean Delbeke
- Neurology Department, Neuroscience Institute, Ghent University , Ghent, Belgium
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Godfraind C, Debelle A, Lonys L, Acuña V, Doguet P, Nonclercq A. Inductive Powering of Subcutaneous Stimulators: Key Parameters and Their Impact on the Design Methodology. Eur J Transl Myol 2016; 26:6040. [PMID: 27478572 PMCID: PMC4942715 DOI: 10.4081/ejtm.2016.6040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inductive powering of implantable medical devices involves numerous factors acting on the system efficiency and safety in adversarial ways. This paper lightens up their role and identifies a procedure enabling the system design. The latter enables the problem to be decoupled into four principal steps: the frequency choice, the magnetic link optimization, the secondary circuit and then finally the primary circuit designs. The methodology has been tested for the powering system of a device requirering a power of 300mW and implanted at a distance of 15 to 30mm from the outside power source. It allowed the identification of the most critical parameters. A satisfying efficiency of 34% was reached at 21mm and tend to validate the proposed design procedure.
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Affiliation(s)
- Carmen Godfraind
- Synergia Medical, Mont-Saint-Guibert, Belgium; Université Libre de Bruxelles, Belgium
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Aqueveque P, Acuña V, Saavedra F, Debelle A, Lonys L, Julémont N, Huberland F, Godfraind C, Nonclercq A. Power Strategy in DC/DC Converters to Increase Efficiency of Electrical Stimulators. Eur J Transl Myol 2016; 26:6061. [PMID: 27990232 PMCID: PMC5128965 DOI: 10.4081/ejtm.2016.6061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Power efficiency is critical for electrical stimulators. Battery life of wearable stimulators and wireless power transmission in implanted systems are common limiting factors. Boost DC/DC converters are typically needed to increase the supply voltage of the output stage. Traditionally, boost DC/DC converters are used with fast control to regulate the supply voltage of the output. However, since stimulators are acting as current sources, such voltage regulation is not needed. Banking on this, this paper presents a DC/DC conversion strategy aiming to increase power efficiency. It compares, in terms of efficiency, the traditional use of boost converters to two alternatives that could be implemented in future hardware designs.
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Lonys L, Vanhoestenberghe A, Huberty V, Hiernaux M, Cauche N, Julémont N, Debelle A, Huberland F, Acuña V, Godfraind C, Devière J, Delchambre A, Mathys P, Nonclercq A. Design and Implementation of a Less Invasive Gastrostimulator. Eur J Transl Myol 2016; 26:6019. [PMID: 27478566 PMCID: PMC4942709 DOI: 10.4081/ejtm.2016.6019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Gastrointestinal stimulator implants have recently shown positive results in helping obese patients lose weight. However, to place the implant, the patient currently needs to undergo an invasive surgical procedure. Our team is aiming for a less invasive procedure to stimulate the stomach with a gastrostimulator. Attempts covered fully endoscopic implantation and, more recently, we have focussed on a single incision laparoscopic procedure. Whatever the chosen implantation solution, the electronic design of the implant system shares many challenges. This paper covers the work achieved to meet these.
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Lejeune L, Prisk GK, Nonclercq A, Migeotte PF. MRI-based aortic blood flow model in 3D ballistocardiography. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2015:7171-4. [PMID: 26737946 DOI: 10.1109/embc.2015.7320046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ballistocardiography (BCG) is a non-invasive technique which measures the acceleration of a body induced by cardiovascular activity, namely the force exerted by the beating heart. A one dimensional aortic flow model based on the transmission lines theory is developped and applied to the simulation of three dimensional BCG. A four-element Windkessel model is used to generate the pressure-wave. Using transverse MRI slices of a human subject, a reconstruction of the aorta allows the extraction of parameters used to relate the local change in mass of the 1D flow model to 3D acceleration BCG. Simulated BCG curves are then compared qualitatively with the ensemble average curves of the same subject recorded in sustained microgravity. Confirming previous studies, the main features of the y-axis are well simulated. The simulated z-axis, never attempted before, shows important similarities. The simulated x-axis is less faithful and suggests the presence of reflections.
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Gilson M, Deliens G, Leproult R, Bodart A, Nonclercq A, Ercek R, Peigneux P. REM-Enriched Naps Are Associated with Memory Consolidation for Sad Stories and Enhance Mood-Related Reactivity. Brain Sci 2015; 6:brainsci6010001. [PMID: 26729175 PMCID: PMC4810171 DOI: 10.3390/brainsci6010001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 12/05/2015] [Accepted: 12/16/2015] [Indexed: 11/16/2022] Open
Abstract
Emerging evidence suggests that emotion and affect modulate the relation between sleep and cognition. In the present study, we investigated the role of rapid-eye movement (REM) sleep in mood regulation and memory consolidation for sad stories. In a counterbalanced design, participants (n = 24) listened to either a neutral or a sad story during two sessions, spaced one week apart. After listening to the story, half of the participants had a short (45 min) morning nap. The other half had a long (90 min) morning nap, richer in REM and N2 sleep. Story recall, mood evolution and changes in emotional response to the re-exposure to the story were assessed after the nap. Although recall performance was similar for sad and neutral stories irrespective of nap duration, sleep measures were correlated with recall performance in the sad story condition only. After the long nap, REM sleep density positively correlated with retrieval performance, while re-exposure to the sad story led to diminished mood and increased skin conductance levels. Our results suggest that REM sleep may not only be associated with the consolidation of intrinsically sad material, but also enhances mood reactivity, at least on the short term.
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Affiliation(s)
- Médhi Gilson
- UR2NF-Neuropsychology and Functional Neuroimaging Research Unit, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
- UNI-ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), avenue F.D. Roosevelt 50, Bruxelles, Belgium.
| | - Gaétane Deliens
- UR2NF-Neuropsychology and Functional Neuroimaging Research Unit, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
- UNI-ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), avenue F.D. Roosevelt 50, Bruxelles, Belgium.
- CO3-Consciousness, Cognition & Computation Group, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
| | - Rachel Leproult
- UR2NF-Neuropsychology and Functional Neuroimaging Research Unit, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
- UNI-ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), avenue F.D. Roosevelt 50, Bruxelles, Belgium.
| | - Alice Bodart
- UR2NF-Neuropsychology and Functional Neuroimaging Research Unit, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
- UNI-ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), avenue F.D. Roosevelt 50, Bruxelles, Belgium.
| | - Antoine Nonclercq
- LISA-Laboratories of Image, Signal processing and Acoustics, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
| | - Rudy Ercek
- LISA-Laboratories of Image, Signal processing and Acoustics, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
| | - Philippe Peigneux
- UR2NF-Neuropsychology and Functional Neuroimaging Research Unit, avenue F.D. Roosevelt 50, Bruxelles 1050, Belgium.
- UNI-ULB Neuroscience Institute, Université Libre de Bruxelles (ULB), avenue F.D. Roosevelt 50, Bruxelles, Belgium.
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De Tiège X, Trotta N, Op de beeck M, Bourguignon M, Marty B, Wens V, Nonclercq A, Goldman S, Van Bogaert P. Neurophysiological activity underlying altered brain metabolism in epileptic encephalopathies with CSWS. Epilepsy Res 2013; 105:316-25. [DOI: 10.1016/j.eplepsyres.2013.02.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 01/03/2013] [Accepted: 02/27/2013] [Indexed: 11/28/2022]
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Nonclercq A, Urbain C, Verheulpen D, Decaestecker C, Van Bogaert P, Peigneux P. Sleep spindle detection through amplitude–frequency normal modelling. J Neurosci Methods 2013; 214:192-203. [DOI: 10.1016/j.jneumeth.2013.01.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 01/17/2013] [Accepted: 01/18/2013] [Indexed: 10/27/2022]
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Nonclercq A, Foulon M, Verheulpen D, De Cock C, Buzatu M, Mathys P, Van Bogaert P. Cluster-based spike detection algorithm adapts to interpatient and intrapatient variation in spike morphology. J Neurosci Methods 2012; 210:259-65. [PMID: 22850558 DOI: 10.1016/j.jneumeth.2012.07.015] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 07/09/2012] [Accepted: 07/23/2012] [Indexed: 10/28/2022]
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Nonclercq A, Lonys L, Vanhoestenberghe A, Demosthenous A, Donaldson N. Safety of multi-channel stimulation implants: a single blocking capacitor per channel is not sufficient after single-fault failure. Med Biol Eng Comput 2012; 50:403-10. [PMID: 22391946 DOI: 10.1007/s11517-012-0889-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 02/26/2012] [Indexed: 10/28/2022]
Abstract
One reason given for placing capacitors in series with stimulation electrodes is that they prevent direct current flow and therefore tissue damage under fault conditions. We show that this is not true for multiplexed multi-channel stimulators with one capacitor per channel. A test bench of two stimulation channels, two stimulation tripoles and a saline bath was used to measure the direct current flowing through the electrodes under two different single fault conditions. The electrodes were passively discharged between stimulation pulses. For the particular condition used (16 mA, 1 ms stimulation pulse at 20 Hz with electrodes placed 5 cm apart), the current ranged from 38 to 326 μA depending on the type of fault. The variation of the fault current with time, stimulation amplitude, stimulation frequency and distance between the electrodes is given. Possible additional methods to improve safety are discussed.
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Affiliation(s)
- Antoine Nonclercq
- Biomedical Stimulation and Monitoring Research Group, Université Libre de Bruxelles, Avenue FD Roosevelt 50 CP165/51, 1050 Brussels, Belgium.
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Nonclercq A, Mathys P. Quantification of Motion Artifact Rejection Due to Active Electrodes and Driven-Right-Leg Circuit in Spike Detection Algorithms. IEEE Trans Biomed Eng 2010; 57. [DOI: 10.1109/tbme.2010.2055867] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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