Independent component analysis (ICA) is a novel technique that calculates independent components from mixed signals. A hypothetical clinical application is to remove artifacts in EEG. The goal of this study was to apply ICA to standard EEG recordings to eliminate well-known artifacts, thus quantifying its efficacy in an objective way. Eighty samples of recordings with spikes and evident artifacts of electrocardiogram (EKG), eye movements, 50-Hz interference, muscle, or electrode artifact were studied. ICA components were calculated using the Joint Approximate Diagonalization of Eigen-matrices (JADE) algorithm. The signal was reconstructed excluding those components related to the artifacts. A normalized correlation coefficient was used as a measure of the changes caused by the suppression of these components. ICA produced an evident clearing-up of signals in all the samples. The morphology and the topography of the spike were very similar before and after the removal of the artifacts. The correlation coefficient showed that the rest of the signal did not change significantly. Two examiners independently looked at the samples to identify the changes in the morphology and location of the discharge and the artifacts. In conclusion, ICA proved to be a useful tool to clean artifacts in short EEG samples, without having the disadvantages associated with the digital filters. The distortion of the interictal activity measured by correlation analysis was minimal.
Summary:Purpose: Independent component analysis (ICA) is a novel algorithm able to separate independent components from complex signals. Studies in interictal EEG demonstrate its usefulness to eliminate eye, muscle, 50-Hz, electrocardiogram (ECG), and electrode artifacts. The goal of this study was to evaluate the usefulness of ICA in removing artifacts in ictal recordings with a known EEG onset.Methods: We studied 20 seizures of nine patients with focal epilepsy monitored in our video-EEG monitoring unit. ICA was applied to remove obvious artifacts in segments at the beginning of the seizure. The final EEGs were exported to the original format and were compared with the original EEG by two blinded examiners. We compared original recordings and the samples cleaned by digital filters (DFs), ICA and ICA plus digital filters (ICA + DFs), evaluating the possibility of finding an ictal pattern, the localization of the onset in area and time, and the global quality of the sample.Results: All the recordings except one (95%) improved after the use of ICA for the elimination of blinking and other artifacts. Three seizures were found in which in the original recordings did not permit us to detect an ictal pattern, and after ICA + DFs, an ictal onset was evident; in two of them, ICA alone was able to show this pattern. The best results in all the scores were obtained with ICA + DF. ICA was better than DFs. The agreement between the two reviewers was highly significant.Conclusions: ICA is useful to remove artifacts from ictal recordings. When applied to ictal recordings, it increases the quality of the recording. In some cases, ICA may be useful to show ictal onsets obscured by artifacts. ICA + DFs obtained the best results regarding removal of the artifacts.
We analyze the compliance behavior of the small-scale fishery boat-owners of the Galapagos Marine Reserve. Our empirical analysis considers aspects related to the participatory management system of the reserve as determinant factors of the decision to violate the regulations. The econometric results indicate that, along with surveillance and fines, the level of legitimacy that norms have among the boat-owners, the sense of belonging of individuals, the legitimacy of their local organizations, as well as their participation levels in these organizations are additional determinant factors in the decision to transgress the agreed regulations. Policy recommendation to improve compliance are also discussed.
In the European context, these concerns are strongly associated with a European Green Deal, with investment in renewables and with digitization. References
Summary
Cardiac changes may occasionally occur during vagus nerve stimulation (VNS) used in epileptic patients. As they can be potentially life‐threatening, it is important to detect them, and this is why an intraoperative test is performed during the implantation. Few cases of asystole during this test have been described. Only one patient with late‐onset bradyarrythmia caused by VNS has been reported. This patient had been implanted 2 years and 4 months before the episode. We present another case of late asystole in a patient whose VNS had been implanted 9 years before the arrhythmia onset. In our patient, each run of stimulation produced bradyarrhythmias and very often severe asystolia due to atrium‐ventricular block.
FIR was impaired in MTLE patients, and FER in both IGE and MTLE, particularly for fear and disgust. Although not statistically significant, those with impaired FER tended to perform more diffuse eye-tracking over the faces and have cognitive dysfunction.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.