Abstract
Scalp electroencephalogram (EEG) is a non-invasive measure of brain activity. It is widely used in several applications including cognitive tasks, sleep stage detection, and seizure prediction. When recorded over several hours, this signal is usually corrupted by noisy disturbances such as experimental errors, environmental interferences, and physiological artifacts. These may generate confounding factors and, therefore, lead to false results. Models able to minimise EEG artifacts are then necessary for improving further analysis and application. In this work, we developed an EEG artifact removal model based on deep convolutional neural networks. The proposed approach was applied on long-term EEGs, acquired from epileptic patients, available in the EPILEPSIAE database. The main goal of our work is to develop a model able to automatically and quickly remove artifacts from EEGs. To develop it, we used EEG segments, manually preprocessed by experts and named target EEG segments. Our approach was evaluated comparing denoised segments with the target segments. Furthermore, we compared our approach with other artifact removal models. Results show that the developed model was able to attenuate the influence of artifacts, present in long-term EEG signals, in a similar way to that performed by experts. Additionally, results evidence that our approach performs better than other artifact removal models, combining a minor reconstruction error with a fast processing. Being a fully automatic and fast model that does not require reference artifact templates, turns it suitable, for example, for continuous preprocessing of long-term electroencephalogram for sleep staging or seizure prediction.
Highlights
Electroencephalogram (EEG) is a nonlinear and nonstationary signal that measures the electrical activity of the brain [1], [2]
This section describes the results obtained for the developed deep convolutional neural network (DCNN)
It is seen that the models started to stabilise around the 300th epoch which means that the number of epochs was not a limiting factor to the learning procedure
Summary
Electroencephalogram (EEG) is a nonlinear and nonstationary signal that measures the electrical activity of the brain [1], [2]. Several electrodes are required to capture them with high spatial resolution [3] Beyond brain information, these electrodes often capture noise, such as environment interference, experimental errors, and physiological artifacts [4]. Experimental errors are usually related with poor electrode adhesion, incorrect scalp cleansing, and subject motion resulting from daily life routine. These errors, that frequently distort the EEG signal, are quite difficult to remove, even with artifact removal approaches [4], [6]. Physiological artifacts are alterations generated from other physiological processes, such as eye movements, muscle activity (chewing, swallowing, talking, and scalp contraction), and cardiac activity. Physiological artifacts generally present a spectrum overlapping the frequencies of interest of the EEG signals [5]–[10]
Published Version
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