Romain Bouet - Academia.edu (original) (raw)
Papers by Romain Bouet
2015 IEEE 12th International Symposium on Biomedical Imaging (ISBI), 2015
2012 IEEE International Conference on Emerging Signal Processing Applications, 2012
High-Frequency Oscillations (HFOs) in the 80-500 Hz band are important biomarkers of epileptogeni... more High-Frequency Oscillations (HFOs) in the 80-500 Hz band are important biomarkers of epileptogenic brain areas and could have a central role in theprocess of epileptogenesis and seizure genesis. Visual marking of HFOs is highly time consuming and tedious especially for long electroencephalographic (EEG) recordings. Automated HFO detection methods are potentially more efficient, repeatable and objective.Therefore,numerous automatic HFOs detection methodshave been developed. Toevaluate and compare theperformance of thesealgorithms in an intuitive and userfriendly framework accessible to researchers, neurologists and students,it is useful to implement the various methodsusing adedicated Graphical User Interfaces (GUI). In this paper we describe a GUI-based tool thatcontains three HFOs detectionmethods. It allowsthe user to test and runthree different methods based respectively on FIR filter, Complex MORLET Wavelet andmatching pursuit (MP). We also show how the GUI can be used to measure the performanceof each method. Generally,high sensitivity entrains high false-positive detection rates. For that, the developed GUI contains a supplementary module that allowsan expert(e.g. neurologist) to reject false detected events and only save the clinically relevant (true) events. In addition, the GUI presented here can be used to perform classification, as well as estimation of duration, frequency and position of different events. The presented software is easy to use and can easily be extended to include further methods. We thus expect it to become a valuable clinical tool for diagnosis of epilepsy and research purposes.
NeuroImage, 2012
Interictal spikes are a hallmark of cortical epileptogenicity; their spatial distribution in the ... more Interictal spikes are a hallmark of cortical epileptogenicity; their spatial distribution in the cortex defines the so-called 'irritative' zone or spiking volume (SV). Delineating the SV precisely is a challenge during the presurgical evaluation of patients with epilepsy. Magnetoencephalography (MEG) recordings enable determination of the brain sources of epileptic spikes using source localization procedures. Most previous clinical MEG studies have relied on dipole modeling of epileptic spikes, which does not permit a volumetric estimation of the spiking cortex. In the present study, we propose a new source modeling procedure, Volumetric Imaging of Epileptic Spikes (VIES). In VIES, the SV is identified as the 3D region where sources of the high frequency activities (> 20 Hz) associated with epileptic spikes are distributed. We localized these sources using a beamforming approach (DICS, Dynamic Imaging of Coherent Neural Sources). To determine the optimal parameters and accuracy of the method, we compared the SV obtained by VIES with the SV defined by the invasive gold standard, intracranial stereotactic EEG recordings (SEEG), in 21 patients with focal epilepsy. Using rigorous validation criteria based on the exact anatomical location of SEEG contacts, we found that the overall sensitivity of VIES for detecting spiking SEEG contacts was 76% and its specificity for correctly identifying nonspiking SEEG contacts was 67%, indicating a good agreement between VIES and SEEG. Moreover, we found that classical dipole clustering was not informative in 9/21 patients, while VIES enable to delineate the SV in all patients. For the 12 patients having a SV delineated both with VIES and dipole clustering, VIES method had higher sensitivity and lower specificity. This proof-of-concept study shows that VIES is a promising approach to non-invasive estimation of the SV in focal epilepsy.
Journal of Urology, 2006
Objectives: To evaluate the risk of hyponatremia and transurethral resection of the prostate (TUR... more Objectives: To evaluate the risk of hyponatremia and transurethral resection of the prostate (TURP) syndrome after bipolar saline TURP in patients with large-volume, benign prostatic hyperplasia and statistically significant comorbidities. Methods: Five patients with large symptomatic benign prostatic hyperplasia and significant comorbidities underwent saline TURP. Data were collected regarding patient profile, prostate weight, operative time, and perioperative events. In particular, we studied and compared the preoperative and postoperative serum sodium concentrations and hematocrit. Results: The mean age was 68 years (range 57 to 76). The mean resection weight of the prostatic chips was 49.6 g (range 37 to 62). Senior urology residents under the supervision of the university faculty performed all procedures. The average operative time was 2 hours, 22 minutes (range 98 to 175 minutes). The mean serum sodium concentration decreased by 1.6 mg/dL (from 138.4 mg/dL preoperatively to 136.8 mg/dL postoperatively). The mean hematocrit decreased by 5.60% (from 40.24% preoperatively to 34.64% postoperatively). Postoperative recovery was uneventful in all 5 patients. Conclusions: Bipolar saline TURP is safe and eliminates the risk of TURP syndrome in high-risk patients with large prostates that require lengthy resection. In addition, the system permits the faculty to spend the time needed for teaching and training urology residents without compromising patient safety.
Brain, 2013
Congenital amusia is a lifelong disorder of music perception and production. The present study in... more Congenital amusia is a lifelong disorder of music perception and production. The present study investigated the cerebral bases of impaired pitch perception and memory in congenital amusia using behavioural measures, magnetoencephalography and voxel-based morphometry. Congenital amusics and matched control subjects performed two melodic tasks (a melodic contour task and an easier transposition task); they had to indicate whether sequences of six tones (presented in pairs) were the same or different. Behavioural data indicated that in comparison with control participants, amusics' short-term memory was impaired for the melodic contour task, but not for the transposition task. The major finding was that pitch processing and short-term memory deficits can be traced down to amusics' early brain responses during encoding of the melodic information. Temporal and frontal generators of the N100m evoked by each note of the melody were abnormally recruited in the amusic brain. Dynamic causal modelling of the N100m further revealed decreased intrinsic connectivity in both auditory cortices, increased lateral connectivity between auditory cortices as well as a decreased right fronto-temporal backward connectivity in amusics relative to control subjects. Abnormal functioning of this fronto-temporal network was also shown during the retention interval and the retrieval of melodic information. In particular, induced gamma oscillations in right frontal areas were decreased in amusics during the retention interval. Using voxel-based morphometry, we confirmed morphological brain anomalies in terms of white and grey matter concentration in the right inferior frontal gyrus and the right superior temporal gyrus in the amusic brain. The convergence between functional and structural brain differences strengthens the hypothesis of abnormalities in the fronto-temporal pathway of the amusic brain. Our data provide first evidence of altered functioning of the auditory cortices during pitch perception and memory in congenital amusia. They further support the hypothesis that in neurodevelopmental disorders impacting high-level functions (here musical abilities), abnormalities in cerebral processing can be observed in early brain responses.
IRBM, 2011
a Inserm U1028, équipe dynamique cérébrale et cognition, centre de recherche en neurosciences de ... more a Inserm U1028, équipe dynamique cérébrale et cognition, centre de recherche en neurosciences de Lyon, centre hospitalier le Vinatier, bâtiment 452, 95, boulevard Pinel,
2015 IEEE 12th International Symposium on Biomedical Imaging (ISBI), 2015
2012 IEEE International Conference on Emerging Signal Processing Applications, 2012
High-Frequency Oscillations (HFOs) in the 80-500 Hz band are important biomarkers of epileptogeni... more High-Frequency Oscillations (HFOs) in the 80-500 Hz band are important biomarkers of epileptogenic brain areas and could have a central role in theprocess of epileptogenesis and seizure genesis. Visual marking of HFOs is highly time consuming and tedious especially for long electroencephalographic (EEG) recordings. Automated HFO detection methods are potentially more efficient, repeatable and objective.Therefore,numerous automatic HFOs detection methodshave been developed. Toevaluate and compare theperformance of thesealgorithms in an intuitive and userfriendly framework accessible to researchers, neurologists and students,it is useful to implement the various methodsusing adedicated Graphical User Interfaces (GUI). In this paper we describe a GUI-based tool thatcontains three HFOs detectionmethods. It allowsthe user to test and runthree different methods based respectively on FIR filter, Complex MORLET Wavelet andmatching pursuit (MP). We also show how the GUI can be used to measure the performanceof each method. Generally,high sensitivity entrains high false-positive detection rates. For that, the developed GUI contains a supplementary module that allowsan expert(e.g. neurologist) to reject false detected events and only save the clinically relevant (true) events. In addition, the GUI presented here can be used to perform classification, as well as estimation of duration, frequency and position of different events. The presented software is easy to use and can easily be extended to include further methods. We thus expect it to become a valuable clinical tool for diagnosis of epilepsy and research purposes.
NeuroImage, 2012
Interictal spikes are a hallmark of cortical epileptogenicity; their spatial distribution in the ... more Interictal spikes are a hallmark of cortical epileptogenicity; their spatial distribution in the cortex defines the so-called 'irritative' zone or spiking volume (SV). Delineating the SV precisely is a challenge during the presurgical evaluation of patients with epilepsy. Magnetoencephalography (MEG) recordings enable determination of the brain sources of epileptic spikes using source localization procedures. Most previous clinical MEG studies have relied on dipole modeling of epileptic spikes, which does not permit a volumetric estimation of the spiking cortex. In the present study, we propose a new source modeling procedure, Volumetric Imaging of Epileptic Spikes (VIES). In VIES, the SV is identified as the 3D region where sources of the high frequency activities (> 20 Hz) associated with epileptic spikes are distributed. We localized these sources using a beamforming approach (DICS, Dynamic Imaging of Coherent Neural Sources). To determine the optimal parameters and accuracy of the method, we compared the SV obtained by VIES with the SV defined by the invasive gold standard, intracranial stereotactic EEG recordings (SEEG), in 21 patients with focal epilepsy. Using rigorous validation criteria based on the exact anatomical location of SEEG contacts, we found that the overall sensitivity of VIES for detecting spiking SEEG contacts was 76% and its specificity for correctly identifying nonspiking SEEG contacts was 67%, indicating a good agreement between VIES and SEEG. Moreover, we found that classical dipole clustering was not informative in 9/21 patients, while VIES enable to delineate the SV in all patients. For the 12 patients having a SV delineated both with VIES and dipole clustering, VIES method had higher sensitivity and lower specificity. This proof-of-concept study shows that VIES is a promising approach to non-invasive estimation of the SV in focal epilepsy.
Journal of Urology, 2006
Objectives: To evaluate the risk of hyponatremia and transurethral resection of the prostate (TUR... more Objectives: To evaluate the risk of hyponatremia and transurethral resection of the prostate (TURP) syndrome after bipolar saline TURP in patients with large-volume, benign prostatic hyperplasia and statistically significant comorbidities. Methods: Five patients with large symptomatic benign prostatic hyperplasia and significant comorbidities underwent saline TURP. Data were collected regarding patient profile, prostate weight, operative time, and perioperative events. In particular, we studied and compared the preoperative and postoperative serum sodium concentrations and hematocrit. Results: The mean age was 68 years (range 57 to 76). The mean resection weight of the prostatic chips was 49.6 g (range 37 to 62). Senior urology residents under the supervision of the university faculty performed all procedures. The average operative time was 2 hours, 22 minutes (range 98 to 175 minutes). The mean serum sodium concentration decreased by 1.6 mg/dL (from 138.4 mg/dL preoperatively to 136.8 mg/dL postoperatively). The mean hematocrit decreased by 5.60% (from 40.24% preoperatively to 34.64% postoperatively). Postoperative recovery was uneventful in all 5 patients. Conclusions: Bipolar saline TURP is safe and eliminates the risk of TURP syndrome in high-risk patients with large prostates that require lengthy resection. In addition, the system permits the faculty to spend the time needed for teaching and training urology residents without compromising patient safety.
Brain, 2013
Congenital amusia is a lifelong disorder of music perception and production. The present study in... more Congenital amusia is a lifelong disorder of music perception and production. The present study investigated the cerebral bases of impaired pitch perception and memory in congenital amusia using behavioural measures, magnetoencephalography and voxel-based morphometry. Congenital amusics and matched control subjects performed two melodic tasks (a melodic contour task and an easier transposition task); they had to indicate whether sequences of six tones (presented in pairs) were the same or different. Behavioural data indicated that in comparison with control participants, amusics' short-term memory was impaired for the melodic contour task, but not for the transposition task. The major finding was that pitch processing and short-term memory deficits can be traced down to amusics' early brain responses during encoding of the melodic information. Temporal and frontal generators of the N100m evoked by each note of the melody were abnormally recruited in the amusic brain. Dynamic causal modelling of the N100m further revealed decreased intrinsic connectivity in both auditory cortices, increased lateral connectivity between auditory cortices as well as a decreased right fronto-temporal backward connectivity in amusics relative to control subjects. Abnormal functioning of this fronto-temporal network was also shown during the retention interval and the retrieval of melodic information. In particular, induced gamma oscillations in right frontal areas were decreased in amusics during the retention interval. Using voxel-based morphometry, we confirmed morphological brain anomalies in terms of white and grey matter concentration in the right inferior frontal gyrus and the right superior temporal gyrus in the amusic brain. The convergence between functional and structural brain differences strengthens the hypothesis of abnormalities in the fronto-temporal pathway of the amusic brain. Our data provide first evidence of altered functioning of the auditory cortices during pitch perception and memory in congenital amusia. They further support the hypothesis that in neurodevelopmental disorders impacting high-level functions (here musical abilities), abnormalities in cerebral processing can be observed in early brain responses.
IRBM, 2011
a Inserm U1028, équipe dynamique cérébrale et cognition, centre de recherche en neurosciences de ... more a Inserm U1028, équipe dynamique cérébrale et cognition, centre de recherche en neurosciences de Lyon, centre hospitalier le Vinatier, bâtiment 452, 95, boulevard Pinel,