Detection of pure epileptic transitory among gamma oscillatory activities in MEG signals by SVD, embedded on a partial dynamic reconfiguration

In this work we used the SVD to reconstruct pure epileptic transitory activities for the definition of the accurate sources responsible of the excessive discharge implied by the transitory hallmark activities in pharmaco resistant epilepsy. We applied firstly an automatic detection of the local peaks of the transitory activities through a thresholding the energy distrubition, then we performed the SVD on the detectable transitory (300 ms window) simulated events to recover only the non contaminated transitory activities by gamma oscillations, we calculate the precision of the SVD to evaluate the robustness of this technique in separation between transitory and gamma oscillations. In second phase we applied the SVD on small window of transitory activities from real MEG signal, we obtained dipolar topographic map for the pure transitory activities, however the time excitation for the recover of pure epileptic transitory activities among the gamma oscillations were very heavy and hence we propose to integrate the SVD on a dynamic partial reconfiguration. This integration were very useful, in fact we did obtained about 27 Times faster in the SVD execution

Evaluation of techniques for predicting seizure Build up

The analysis of electrophysiological signal of scalp: EEG (electroencephalography), MEG (magnetoencephalography) and depth (intracerebral EEG) IEEG is a way to delimit epileptogenic zone (EZ). These epileptic signals present two different activities (oscillations and spikes) which can be overlapped in the time frequency plane. Automatic recognition of epileptic seizure occurrence needs several preprocessing steps. In this study, we evaluated two filtering techniques: the stationary wavelet transforms (SWT) and the Despikifying in order to extract pre ictal gamma oscillations (bio markers of seizure build up). Then, we used a temporal basis set of Jmail et al 2017 as a preprocessing step to evaluate the performance of both technique. Moreover, we used time-frequency and spatio-temporal mapping of simulated and real data for both techniques in order to predict seizure build up (in time and space). We concluded that SWT can detect the oscillations, but Despikyfying is more robust than SWT in reconstructing pure pre ictal gamma oscillations and hence in predicting seizure build up.Comment: 10 pages and 7 figure

Integration of stationary wavelet transform on a dynamic partial reconfiguration: case study separating preictal gamma oscillations from transitory activities for early build up epileptic seizure

To define the neural networks responsible of the epileptic seizure, we had to study the electrophysiological signal in a proper way. The early recognition of the seizure build up could also be defined through the time space mapping of the preictal gamma oscillations. The electrophysiological signals present three types of wave: oscillations, spikes, and a mixture of both. Recent studies prove that spikes and oscillations should be separated efficiently to define the accurate neural connectivity for each activity. However retrieving the transitory activity is a sensitive task due to the frequency interfering between the gamma oscillatory and the transitory activities. Many filtering techniques are highlighted to ensure a good separation: reducing false oscillations in the transitory activity and vis versa. However and for a big data set, this separation necessitate a big consumption in time execution, this constraint will be overcome using embedded architecture. The integration of these filtering techniques would also lead to creating instantaneous monitoring of the seizure recognition, build up and neurofeedback devices. We propose here to implement the stationary wavelet transform as a convenient filtering technique to keep only the preictal gamma oscillations on a partial dynamic configuration, then we will use the same architecture to integrate the time space mapping for an early recognition of the build up seizure. We proved a faster recognition of the build up seizure through the non contaminated preictal gamma oscillations time space mapping (about 40 times faster), obtained by the integration of the wavelet transform.Comment: 14 pages, 9 figures and 3 table