HAL (Le Centre pour la Communication Scientifique Directe), Nov 20, 2006
The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body sur... more The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body surface potential mapping (BSPM) is studied, using a 64-channel high-resolution ECG system. The index associated to each lead is the shape difference between its ECG wave and a reference computed taking into account all the leads on the same column. The reference is either a selected real wave or a synthetic signal computed by integral shape averaging (ISA). Better results are obtained with the ISA signal using the distribution function method (DFM) for computing the shape difference. The spatial dispersion of ECG waves is showed to allow the separation of patients after myocardial infarction (MI) from healthy subjects. In addition, the reference signal position for each column is computed. The path linking these positions appears as an invariant, i.e., it is independent of the subject and the ECG wave.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 28, 2012
In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying in... more In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period is varying function of time, during exercise. This technique allows the estimation of the autonomic nervous system modulation (ANS) from the beat occurrences. The estimated respiratory sinus arrhythmia is then filtered in the time-frequency domain around the respiration using a time-varying filter. It is proven that the Spectrogram is a convenient time-frequency representation that allows the implementation of such filter. The recorded data comes from exercise test performed by ten heart transplant patients. The magnitude of the filtered modulation of the heart rate due to respiration is compared to the date of transplantation taking into account the volume of respiration. It reveals that the normalized magnitude of the filtered variability, is significantly increased as the age of transplantation is higher with a high correlation coefficient (R=0.74, p=0.01). This correlation raised to 0.82 when considering dynamic behavior of the parameters. Applied to our dataset, standard parameter fails to exhibit such correlation.
Zenodo (CERN European Organization for Nuclear Research), Aug 17, 2022
In this preliminary study, we introduce the use of personalized high-density optodes montage for ... more In this preliminary study, we introduce the use of personalized high-density optodes montage for cerebellar fNIRS acquisitions. One subject performed left or right finger tapping tasks consecutively with fNIRS and fMRI. Conclusive ipsilateral cerebellar activations were observed in the fNIRS HRF and supported by strong clusters in the fMRI. Introduction: The recent blossoming of cerebellar neuroscience calls for novel and flexible techniques for further investigations. In a previous study, we proved the feasibility, through simple montage, of measuring cerebellar hemodynamics with fNIRS 1 , and further validated it with fMRI 2. To better tackle the physiological challenge of accessing the cerebellum with NIRS, we assess here the advantage of using personalized high-density layouts of optodes, optimized in terms of sensitivity, and their impact on the HRF estimation. Methods: One healthy right-handed male subject (27y) was recruited. A Monte-Carlo based method, implemented on NIRSTORM, was used to derive a personalized dense optodes positioning 3 , sensitivity-optimized using the subject's anatomical MRI (T1-weighted). The subject participated consecutively in one CW-fNIRS and one fMRI session, by performing an auditory cued finger tapping task with alternating hands (20 trials: 10s activity + 30 to 38s random rest). Guided by a neuronavigation system, the optodes (incl. one SS per hemisphere) were glued on the subject's head. fMRI was acquired using GRE-EPI sequences (3.7 mm3, TR = 2 s, TE = 25 ms, 41 slices). Both fNIRS and fMRI signals were processed following standard pipelines and a GLM block-design framework for single participant. Results: A high sensitivity montage was achieved with 3 sources and 5 detectors for each cerebellar hemisphere (Fig 1A). Ipsilateral cerebellar activations were clearly observed (Fig 1B, for readability only S7D7, S7D9 are displayed for the left hemisphere, and S2D3, S3D1 for the right one). Accordingly, strong ipsilateral clusters were found in the fMRI (p < 0.001 FWE corrected at peak level) (Fig 1C). Precisely, [Left] (resp. [Right]) condition elicited activations in Crus-1 and lobule 8 cerebellar regions. Critically, Crus-1 activations were bilateral, though stronger in the ipsilateral cluster for each condition, matching well with the hemodynamics as measured by fNIRS. Conclusion: This study demonstrates the feasibility and interest of personalized high-density fNIRS cerebellar montage to improve the quality of the acquired hemodynamic signals. This approach provides the potential to perform cerebellar 3D source reconstruction and also coherent spatio-temporal filtering to better separate the bona fide neuronal activity from physiological confounding components. At the more practical level, more participants are currently being recruited to fully assess the intersubject variability.
In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying in... more In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period is varying function of time, during exercise. This technique allows the estimation of the autonomic nervous system modulation (ANS) from the beat occurrences. The estimated respiratory sinus arrhythmia is then filtered in the time-frequency domain around the respiration using a time-varying filter. It is proven that the Spectrogram is a convenient time-frequency representation that allows the implementation of such filter. The recorded data comes from exercise test performed by ten heart transplant patients. The magnitude of the filtered modulation of the heart rate due to respiration is compared to the date of transplantation taking into account the volume of respiration. It reveals that the normalized magnitude of the filtered variability, is significantly increased as the age of transplantation is higher with a high correlation coefficient (R=0.74, p=0.01). This correlation raised to 0.82 when considering dynamic behavior of the parameters. Applied to our dataset, standard parameter fails to exhibit such correlation.
Frontiers in Applied Mathematics and Statistics, Aug 2, 2019
Background: The study of repetitive (quasi-periodic) spatio-temporal patterns in complex dynamica... more Background: The study of repetitive (quasi-periodic) spatio-temporal patterns in complex dynamical systems with a well defined spatial structure may be complicated if the recurrent behavior is confined to specific local regions, where it lasts for a limited time. This can decrease the efficacy of recurrence plots (RPs) in recognizing such patterns. It then becomes important to first detect whether repetitive spatio-temporal patterns are present, and if so, where they are located (both in space and time), to facilitate a focused RP analysis approach. This study proposes a novel framework for spatio-temporal detection of local recurrence of a quasi-periodic nature in complex dynamical systems. A motivating application for this framework is the analysis of atrial fibrillation to better understand the heart tissue involved. Methods: The spatio-temporal data observed from the system are decomposed by means of principal component analysis to identify the points in the spatial structure exhibiting quasi-periodic recurrent patterns. The frequency content of the principal components is used to determine if such patterns are present, and the corresponding eigenvectors are used to identify the points associated with those components. Geometric information about proximity of these points is used to cluster them into local regions. A sliding temporal window is used to detect the start and end of each pattern. Results: A first simulation shows how the proposed framework can handle multiple recurrent patterns simultaneously occurring in a spatial structure of a dynamical system. A second simulation shows how the method can handle more complicated patterns like 2D nonlinear spiraling waves, typical of many diffusion processes. The framework is then applied to real data to detect recurrent patterns in wave fronts propagating inside the heart during atrial fibrillation. This analysis can unveil regions of recurrence in the atria that were not visible with standard RP analysis. Conclusion: A novel framework for detecting spatio-temporal repetitive patterns in complex dynamical systems is introduced. It allows retrieve the correct recurrences associated with known 2D traveling waves, while the same information is not visible with standard RP analysis. This framework can be effectively used to investigate recurrence in real dynamical systems as cardiac arrhythmia.
Prédiction non invasive du suivi au décours d'une ablation par cathéter d'une fibrillation atrial... more Prédiction non invasive du suivi au décours d'une ablation par cathéter d'une fibrillation atriale persistante par l'analyse informatisée de l'amplitude des ondes de fibrillation atriale sur un tracé ECG à multiples dérivations
HAL (Le Centre pour la Communication Scientifique Directe), Sep 1, 2017
Propagation of electrical atrial activity (AA) during atrial fibrillation (AF) is a process chara... more Propagation of electrical atrial activity (AA) during atrial fibrillation (AF) is a process characterized by different short-and long-term recurrence behaviours. Two antithetical (not mutually exclusive) hypotheses are proposed to noninvasively describe this nonstationary behaviour. The first hypothesis (H1) assumes a process with stationary spatial properties of AA propagation, but time-varying frequency properties, and vice versa for the second (H2). Based on H1 and H2, two phenomenological models were proposed, both able to replicate observations on AF patients, and a novel measure was introduced to assess the spatial variability of AA propagation (SVAAP) over short and long AA segments. Validity of the models was tested by looking at the relation between SVAAP-long and SVAAPshort on real observations from AF patients (high-density body surface potential maps recorded in 75 patients affected by persistent AF). H1 is confirmed if SVAAP-short is approximately equal to SVAAP-long. H2 if SVAAP-short is less than SVAAP-long. Results confirmed H2, showing that AA propagation during AF has strong nonstationary spatial properties. This could suggest new parameters to characterise AF substrate and predict therapy outcome.
2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Nov 1, 2021
Functional Magnetic Resonance Imaging (fMRI) has been so far the golden standard to study the fun... more Functional Magnetic Resonance Imaging (fMRI) has been so far the golden standard to study the functional aspects of the cerebellum. In this paper, a low-cost alternative imaging, i.e. functional Near-Infrared Spectroscopy (fNIRS) is demonstrated to achieve successful measurements of the cerebellar hemodynamics towards the challenging observation of motor and cognitive processes at the cerebellar level. The excitation and reception optodes need to be properly placed to circumvent a major hindering from the shielding by the neck muscles. A simple experimental protocol, i.e. finger tapping task, was implemented to observe the subject's engagement and the presence of functional asymmetries. Marked differences among subjects with different levels of lateralization were clearly noticed in terms of activation and latencies, together with peaks in the hemodynamic response following neural activation. These preliminary results suggest also differences in the hemodynamic behavior between the brain and the cerebellum and encourage future and extended analysis in this direction. Clinical Relevance-This establishes the possibility to use a novel technique (fNIRS) to study cerebellar hemodynamics instead of fMRI.
The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body sur... more The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body surface potential mapping (BSPM) is studied, using a 64-channel high-resolution ECG system. The index associated to each lead is the shape difference between its ECG wave and a reference computed taking into account all the leads on the same column. The reference is either a selected real wave or a synthetic signal computed by integral shape averaging (ISA). Better results are obtained with the ISA signal using the distribution function method (DFM) for computing the shape difference. The spatial dispersion of ECG waves is showed to allow the separation of patients after myocardial infarction (MI) from healthy subjects. In addition, the reference signal position for each column is computed. The path linking these positions appears as an invariant, i.e., it is independent of the subject and the ECG wave.
HAL (Le Centre pour la Communication Scientifique Directe), Nov 18, 2020
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
HAL (Le Centre pour la Communication Scientifique Directe), Mar 28, 2022
Validation of fNIRS as a viable tool for cerebellar explorations, consistent with fMRI • Combinin... more Validation of fNIRS as a viable tool for cerebellar explorations, consistent with fMRI • Combining fMRI and fNIRS is a promising approach to investigate neural activation with finer time/space resolution • Possibility to perform functional studies of the synergies between brain cortex, cerebellar circuitry, and deep brain structures, e.g. basal ganglia • Peculiar hemodynamics at the cerebellar level call for further investigations of the interplay between ipsi-and contra-lateral responses and hemisphere dominance • Multimodal investigations by adding EEG for a robust exploration of the finest timing aspects of cerebellar neural responses to fully complement fNIRS/fMRI RESULTS METHODS • One right-handed subject from our cohort selected to perform a finger tapping task with sequential fNIRS and fMRI recordings • 3 runs summing up to 20 blocks (10 left hand + 10 right) and each block consisting of 10 s of activity + 30 to 35 s of rest • 2 long channels (Source-Detector = 3cm) and 2 short separation channels on each cerebellar hemisphere using NIRx Sport2 device • fMRI data acquired on a 3T Siemens Magnetom Skyra MRI system. Volumes acquired using a T2* weighted SMS-EPI sequence (vox= 2.5mm) with temporal resolution of 1 second.
2020 5th International Conference on Advanced Technologies for Signal and Image Processing (ATSIP), 2020
This paper deals with the diagnosis of intellectual precocity in gifted children (GC) cases. The ... more This paper deals with the diagnosis of intellectual precocity in gifted children (GC) cases. The P300 component is usually used for giftedness identification. By the use of empirical mode decomposition (EMD), a significant P300 detection is obtained through electroencephalogram signals (EEG). The novelty of the proposed work is to speed up the intellectual ability characterization based on statistical features extraction from P300 response. In order to get an optimized number of estimated information, a selection technique based on the characterization degree criterion (CD-J) is then introduced. This allows a considerably computing time decreasing and an excessive performance of the achieved results. Besides that, the proposed analysis method is applied on (GC) dataset, covering a parental relationship. Compared to the previous works, the proposed approach seems to be promising and useful for the characterization children and their diagnostic improvement.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 13, 2021
INTRODUCTIOǸ Cerebellum CONCLUSIONS • fNIRS is able to discriminate between baseline condition an... more INTRODUCTIOǸ Cerebellum CONCLUSIONS • fNIRS is able to discriminate between baseline condition and experimental session, detecting hemodynamic changes due to cerebellar activity (BOLD paradigm).
HAL (Le Centre pour la Communication Scientifique Directe), Nov 20, 2006
The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body sur... more The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body surface potential mapping (BSPM) is studied, using a 64-channel high-resolution ECG system. The index associated to each lead is the shape difference between its ECG wave and a reference computed taking into account all the leads on the same column. The reference is either a selected real wave or a synthetic signal computed by integral shape averaging (ISA). Better results are obtained with the ISA signal using the distribution function method (DFM) for computing the shape difference. The spatial dispersion of ECG waves is showed to allow the separation of patients after myocardial infarction (MI) from healthy subjects. In addition, the reference signal position for each column is computed. The path linking these positions appears as an invariant, i.e., it is independent of the subject and the ECG wave.
HAL (Le Centre pour la Communication Scientifique Directe), Aug 28, 2012
In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying in... more In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period is varying function of time, during exercise. This technique allows the estimation of the autonomic nervous system modulation (ANS) from the beat occurrences. The estimated respiratory sinus arrhythmia is then filtered in the time-frequency domain around the respiration using a time-varying filter. It is proven that the Spectrogram is a convenient time-frequency representation that allows the implementation of such filter. The recorded data comes from exercise test performed by ten heart transplant patients. The magnitude of the filtered modulation of the heart rate due to respiration is compared to the date of transplantation taking into account the volume of respiration. It reveals that the normalized magnitude of the filtered variability, is significantly increased as the age of transplantation is higher with a high correlation coefficient (R=0.74, p=0.01). This correlation raised to 0.82 when considering dynamic behavior of the parameters. Applied to our dataset, standard parameter fails to exhibit such correlation.
Zenodo (CERN European Organization for Nuclear Research), Aug 17, 2022
In this preliminary study, we introduce the use of personalized high-density optodes montage for ... more In this preliminary study, we introduce the use of personalized high-density optodes montage for cerebellar fNIRS acquisitions. One subject performed left or right finger tapping tasks consecutively with fNIRS and fMRI. Conclusive ipsilateral cerebellar activations were observed in the fNIRS HRF and supported by strong clusters in the fMRI. Introduction: The recent blossoming of cerebellar neuroscience calls for novel and flexible techniques for further investigations. In a previous study, we proved the feasibility, through simple montage, of measuring cerebellar hemodynamics with fNIRS 1 , and further validated it with fMRI 2. To better tackle the physiological challenge of accessing the cerebellum with NIRS, we assess here the advantage of using personalized high-density layouts of optodes, optimized in terms of sensitivity, and their impact on the HRF estimation. Methods: One healthy right-handed male subject (27y) was recruited. A Monte-Carlo based method, implemented on NIRSTORM, was used to derive a personalized dense optodes positioning 3 , sensitivity-optimized using the subject's anatomical MRI (T1-weighted). The subject participated consecutively in one CW-fNIRS and one fMRI session, by performing an auditory cued finger tapping task with alternating hands (20 trials: 10s activity + 30 to 38s random rest). Guided by a neuronavigation system, the optodes (incl. one SS per hemisphere) were glued on the subject's head. fMRI was acquired using GRE-EPI sequences (3.7 mm3, TR = 2 s, TE = 25 ms, 41 slices). Both fNIRS and fMRI signals were processed following standard pipelines and a GLM block-design framework for single participant. Results: A high sensitivity montage was achieved with 3 sources and 5 detectors for each cerebellar hemisphere (Fig 1A). Ipsilateral cerebellar activations were clearly observed (Fig 1B, for readability only S7D7, S7D9 are displayed for the left hemisphere, and S2D3, S3D1 for the right one). Accordingly, strong ipsilateral clusters were found in the fMRI (p < 0.001 FWE corrected at peak level) (Fig 1C). Precisely, [Left] (resp. [Right]) condition elicited activations in Crus-1 and lobule 8 cerebellar regions. Critically, Crus-1 activations were bilateral, though stronger in the ipsilateral cluster for each condition, matching well with the hemodynamics as measured by fNIRS. Conclusion: This study demonstrates the feasibility and interest of personalized high-density fNIRS cerebellar montage to improve the quality of the acquired hemodynamic signals. This approach provides the potential to perform cerebellar 3D source reconstruction and also coherent spatio-temporal filtering to better separate the bona fide neuronal activity from physiological confounding components. At the more practical level, more participants are currently being recruited to fully assess the intersubject variability.
In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying in... more In this paper, we analyze the heart rate variability (HRV), obtained by using the time-varying integral pulse frequency modulation (TVIPFM) which is well adapted to the exercise stress testing. We consider that the mean heart period is varying function of time, during exercise. This technique allows the estimation of the autonomic nervous system modulation (ANS) from the beat occurrences. The estimated respiratory sinus arrhythmia is then filtered in the time-frequency domain around the respiration using a time-varying filter. It is proven that the Spectrogram is a convenient time-frequency representation that allows the implementation of such filter. The recorded data comes from exercise test performed by ten heart transplant patients. The magnitude of the filtered modulation of the heart rate due to respiration is compared to the date of transplantation taking into account the volume of respiration. It reveals that the normalized magnitude of the filtered variability, is significantly increased as the age of transplantation is higher with a high correlation coefficient (R=0.74, p=0.01). This correlation raised to 0.82 when considering dynamic behavior of the parameters. Applied to our dataset, standard parameter fails to exhibit such correlation.
Frontiers in Applied Mathematics and Statistics, Aug 2, 2019
Background: The study of repetitive (quasi-periodic) spatio-temporal patterns in complex dynamica... more Background: The study of repetitive (quasi-periodic) spatio-temporal patterns in complex dynamical systems with a well defined spatial structure may be complicated if the recurrent behavior is confined to specific local regions, where it lasts for a limited time. This can decrease the efficacy of recurrence plots (RPs) in recognizing such patterns. It then becomes important to first detect whether repetitive spatio-temporal patterns are present, and if so, where they are located (both in space and time), to facilitate a focused RP analysis approach. This study proposes a novel framework for spatio-temporal detection of local recurrence of a quasi-periodic nature in complex dynamical systems. A motivating application for this framework is the analysis of atrial fibrillation to better understand the heart tissue involved. Methods: The spatio-temporal data observed from the system are decomposed by means of principal component analysis to identify the points in the spatial structure exhibiting quasi-periodic recurrent patterns. The frequency content of the principal components is used to determine if such patterns are present, and the corresponding eigenvectors are used to identify the points associated with those components. Geometric information about proximity of these points is used to cluster them into local regions. A sliding temporal window is used to detect the start and end of each pattern. Results: A first simulation shows how the proposed framework can handle multiple recurrent patterns simultaneously occurring in a spatial structure of a dynamical system. A second simulation shows how the method can handle more complicated patterns like 2D nonlinear spiraling waves, typical of many diffusion processes. The framework is then applied to real data to detect recurrent patterns in wave fronts propagating inside the heart during atrial fibrillation. This analysis can unveil regions of recurrence in the atria that were not visible with standard RP analysis. Conclusion: A novel framework for detecting spatio-temporal repetitive patterns in complex dynamical systems is introduced. It allows retrieve the correct recurrences associated with known 2D traveling waves, while the same information is not visible with standard RP analysis. This framework can be effectively used to investigate recurrence in real dynamical systems as cardiac arrhythmia.
Prédiction non invasive du suivi au décours d'une ablation par cathéter d'une fibrillation atrial... more Prédiction non invasive du suivi au décours d'une ablation par cathéter d'une fibrillation atriale persistante par l'analyse informatisée de l'amplitude des ondes de fibrillation atriale sur un tracé ECG à multiples dérivations
HAL (Le Centre pour la Communication Scientifique Directe), Sep 1, 2017
Propagation of electrical atrial activity (AA) during atrial fibrillation (AF) is a process chara... more Propagation of electrical atrial activity (AA) during atrial fibrillation (AF) is a process characterized by different short-and long-term recurrence behaviours. Two antithetical (not mutually exclusive) hypotheses are proposed to noninvasively describe this nonstationary behaviour. The first hypothesis (H1) assumes a process with stationary spatial properties of AA propagation, but time-varying frequency properties, and vice versa for the second (H2). Based on H1 and H2, two phenomenological models were proposed, both able to replicate observations on AF patients, and a novel measure was introduced to assess the spatial variability of AA propagation (SVAAP) over short and long AA segments. Validity of the models was tested by looking at the relation between SVAAP-long and SVAAPshort on real observations from AF patients (high-density body surface potential maps recorded in 75 patients affected by persistent AF). H1 is confirmed if SVAAP-short is approximately equal to SVAAP-long. H2 if SVAAP-short is less than SVAAP-long. Results confirmed H2, showing that AA propagation during AF has strong nonstationary spatial properties. This could suggest new parameters to characterise AF substrate and predict therapy outcome.
2021 43rd Annual International Conference of the IEEE Engineering in Medicine & Biology Society (EMBC), Nov 1, 2021
Functional Magnetic Resonance Imaging (fMRI) has been so far the golden standard to study the fun... more Functional Magnetic Resonance Imaging (fMRI) has been so far the golden standard to study the functional aspects of the cerebellum. In this paper, a low-cost alternative imaging, i.e. functional Near-Infrared Spectroscopy (fNIRS) is demonstrated to achieve successful measurements of the cerebellar hemodynamics towards the challenging observation of motor and cognitive processes at the cerebellar level. The excitation and reception optodes need to be properly placed to circumvent a major hindering from the shielding by the neck muscles. A simple experimental protocol, i.e. finger tapping task, was implemented to observe the subject's engagement and the presence of functional asymmetries. Marked differences among subjects with different levels of lateralization were clearly noticed in terms of activation and latencies, together with peaks in the hemodynamic response following neural activation. These preliminary results suggest also differences in the hemodynamic behavior between the brain and the cerebellum and encourage future and extended analysis in this direction. Clinical Relevance-This establishes the possibility to use a novel technique (fNIRS) to study cerebellar hemodynamics instead of fMRI.
The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body sur... more The spatial distribution of the shape of the electrocardiography (ECG) waves obtained by body surface potential mapping (BSPM) is studied, using a 64-channel high-resolution ECG system. The index associated to each lead is the shape difference between its ECG wave and a reference computed taking into account all the leads on the same column. The reference is either a selected real wave or a synthetic signal computed by integral shape averaging (ISA). Better results are obtained with the ISA signal using the distribution function method (DFM) for computing the shape difference. The spatial dispersion of ECG waves is showed to allow the separation of patients after myocardial infarction (MI) from healthy subjects. In addition, the reference signal position for each column is computed. The path linking these positions appears as an invariant, i.e., it is independent of the subject and the ECG wave.
HAL (Le Centre pour la Communication Scientifique Directe), Nov 18, 2020
HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific re... more HAL is a multidisciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.
HAL (Le Centre pour la Communication Scientifique Directe), Mar 28, 2022
Validation of fNIRS as a viable tool for cerebellar explorations, consistent with fMRI • Combinin... more Validation of fNIRS as a viable tool for cerebellar explorations, consistent with fMRI • Combining fMRI and fNIRS is a promising approach to investigate neural activation with finer time/space resolution • Possibility to perform functional studies of the synergies between brain cortex, cerebellar circuitry, and deep brain structures, e.g. basal ganglia • Peculiar hemodynamics at the cerebellar level call for further investigations of the interplay between ipsi-and contra-lateral responses and hemisphere dominance • Multimodal investigations by adding EEG for a robust exploration of the finest timing aspects of cerebellar neural responses to fully complement fNIRS/fMRI RESULTS METHODS • One right-handed subject from our cohort selected to perform a finger tapping task with sequential fNIRS and fMRI recordings • 3 runs summing up to 20 blocks (10 left hand + 10 right) and each block consisting of 10 s of activity + 30 to 35 s of rest • 2 long channels (Source-Detector = 3cm) and 2 short separation channels on each cerebellar hemisphere using NIRx Sport2 device • fMRI data acquired on a 3T Siemens Magnetom Skyra MRI system. Volumes acquired using a T2* weighted SMS-EPI sequence (vox= 2.5mm) with temporal resolution of 1 second.
2020 5th International Conference on Advanced Technologies for Signal and Image Processing (ATSIP), 2020
This paper deals with the diagnosis of intellectual precocity in gifted children (GC) cases. The ... more This paper deals with the diagnosis of intellectual precocity in gifted children (GC) cases. The P300 component is usually used for giftedness identification. By the use of empirical mode decomposition (EMD), a significant P300 detection is obtained through electroencephalogram signals (EEG). The novelty of the proposed work is to speed up the intellectual ability characterization based on statistical features extraction from P300 response. In order to get an optimized number of estimated information, a selection technique based on the characterization degree criterion (CD-J) is then introduced. This allows a considerably computing time decreasing and an excessive performance of the achieved results. Besides that, the proposed analysis method is applied on (GC) dataset, covering a parental relationship. Compared to the previous works, the proposed approach seems to be promising and useful for the characterization children and their diagnostic improvement.
HAL (Le Centre pour la Communication Scientifique Directe), Apr 13, 2021
INTRODUCTIOǸ Cerebellum CONCLUSIONS • fNIRS is able to discriminate between baseline condition an... more INTRODUCTIOǸ Cerebellum CONCLUSIONS • fNIRS is able to discriminate between baseline condition and experimental session, detecting hemodynamic changes due to cerebellar activity (BOLD paradigm).
Uploads
Papers by Olivier Meste