Classifying BCI signals from novice users with Extreme Learning Machine

Volume 15, Issue 1 Previous ArticleNext Article Classifying BCI signals from novice users with extreme learning machine Germán Rodríguez-Bermúdez / Andrés Bueno-Crespo / F. José Martinez-Albaladejo Published Online: 2017-07-07 | DOI: https://doi.org/10.1515/phys-2017-0056 OPEN ACCESS DOWNLOAD PDF Abstract Brain computer interface (BCI) allows to control external devices only with the electrical activity of the brain. In order to improve the system, several approaches have been proposed. However it is usual to test algorithms with standard BCI signals from experts users or from repositories available on Internet. In this work, extreme learning machine (ELM) has been tested with signals from 5 novel users to compare with standard classification algorithms. Experimental results show that ELM is a suitable method to classify electroencephalogram signals from novice users.Ingeniería, Industria y Construcció

A Deep Evolutionary Approach to Bioinspired Classifier Optimisation for Brain-Machine Interaction

This study suggests a new approach to EEG data classification by exploring the idea of using evolutionary computation to both select useful discriminative EEG features and optimise the topology of Artificial Neural Networks. An evolutionary algorithm is applied to select the most informative features from an initial set of 2550 EEG statistical features. Optimisation of a Multilayer Perceptron (MLP) is performed with an evolutionary approach before classification to estimate the best hyperparameters of the network. Deep learning and tuning with Long Short-Term Memory (LSTM) are also explored, and Adaptive Boosting of the two types of models is tested for each problem. Three experiments are provided for comparison using different classifiers: One for attention state classification, one for emotional sentiment classification, and a third experiment in which the goal is to guess the number a subject is thinking of. The obtained results show that an Adaptive Boosted LSTM can achieve an accuracy of 84.44%, 97.06%, and 9.94% on the attentional, emotional, and number datasets, respectively. An evolutionary-optimised MLP achieves results close to the Adaptive Boosted LSTM for the two first experiments and significantly higher for the number-guessing experiment with an Adaptive Boosted DEvo MLP reaching 31.35%, while being significantly quicker to train and classify. In particular, the accuracy of the nonboosted DEvo MLP was of 79.81%, 96.11%, and 27.07% in the same benchmarks. Two datasets for the experiments were gathered using a Muse EEG headband with four electrodes corresponding to TP9, AF7, AF8, and TP10 locations of the international EEG placement standard. The EEG MindBigData digits dataset was gathered from the TP9, FP1, FP2, and TP10 locations

An efficient emotion classification system using EEG

Emotion classification via Electroencephalography (EEG) is used to find the relationships between EEG signals and human emotions. There are many available channels, which consist of electrodes capturing brainwave activity. Some applications may require a reduced number of channels and frequency bands to shorten the computation time, facilitate human comprehensibility, and develop a practical wearable. In prior research, different sets of channels and frequency bands have been used. In this study, a systematic way of selecting the set of channels and frequency bands has been investigated, and results shown that by using the reduced number of channels and frequency bands, it can achieve similar accuracies. The study also proposed a method used to select the appropriate features using the Relief F method. The experimental results of this study showed that the method could reduce and select appropriate features confidently and efficiently. Moreover, the Fuzzy Support Vector Machine (FSVM) is used to improve emotion classification accuracy, as it was found from this research that it performed better than the Support Vector Machine (SVM) in handling the outliers, which are typically presented in the EEG signals. Furthermore, the FSVM is treated as a black-box model, but some applications may need to provide comprehensible human rules. Therefore, the rules are extracted using the Classification and Regression Trees (CART) approach to provide human comprehensibility to the system. The FSVM and rule extraction experiments showed that The FSVM performed better than the SVM in classifying the emotion of interest used in the experiments, and rule extraction from the FSVM utilizing the CART (FSVM-CART) had a good trade-off between classification accuracy and human comprehensibility

Graph neural networks for seizure discrimination based on electroencephalogram analysis

Este estudio presenta una investigación sobre la clasificación de Convulsiones Psicógenas No Epilépticas (PNES) y Convulsiones Epilépticas (ES) utilizando datos de EEG y Redes Neuronales de Grafos (GNN). El modelo propuesto muestra un rendimiento destacable, superando los resultados previos del estado del arte y logrando una precisión notable en la clasificación ternaria. Mediante el uso de una arquitectura GNN, el modelo distingue de manera efectiva entre PNES y ES con una precisión del 92.9%. Además, al emplear la validación cruzada "Leave One Group Out", el modelo logra una precisión aún mayor del 97.58%, superando la precisión más alta reportada en el estado del arte de 94.4%. Asimismo, al ampliar la clasificación para incluir a pacientes sanos, el modelo alcanza una precisión del 91.12%, superando la mejor precisión conocida del estado del arte de 85.7%. Estos hallazgos resaltan el potencial del modelo para clasificar y diferenciar de manera precisa estas condiciones médicas utilizando datos de EEG. El trabajo futuro incluye la exploración de biomarcadores para la clasificación binaria utilizando las capacidades de explicabilidad del modelo, contribuyendo al desarrollo de herramientas de diagnóstico objetivas y estrategias de tratamiento personalizadas. Además, este estudio compara el rendimiento, las metodologías y los conjuntos de datos de estudios similares del estado del arte, proporcionando una visión general completa de la investigación en clasificación de convulsiones. En conclusión, este estudio demuestra el éxito del modelo propuesto en la clasificación de PNES y ES, allanando el camino para futuros avances en el campo y beneficiando a pacientes y profesionales de la salud en el diagnóstico y tratamiento.This study presents a research investigation on the classification of Psychogenic Non-Epileptic Seizures (PNES) and Epileptic Seizures (ES) using EEG data and Graph Neural Networks (GNN). The proposed model demonstrates outstanding performance, surpassing previous state-of-the-art results and achieving remarkable accuracy in ternary classification. By utilizing a GNN architecture, the model effectively distinguishes between PNES and ES with an accuracy of 92.9%. Moreover, when employing Leave One Group Out crossvalidation, the model achieves an even higher accuracy of 97.58%, outperforming the highest reported state-of-the-art accuracy of 94.4%. Furthermore, by extending the classification to include healthy patients, the model achieves an accuracy of 91.12%, surpassing the bestknown state-of-the-art accuracy of 85.7%. These findings highlight the potential of the model in accurately classifying and differentiating these medical conditions using EEG data. Future work includes the exploration of biomarkers for binary classification using the model's explainability capabilities, contributing to the development of objective diagnostic tools and personalized treatment strategies. Additionally, this study compares the performance, methodologies, and datasets of similar studies from the state-of-the-art, providing a comprehensive overview of seizure classification research. In conclusion, this study demonstrates the success of the proposed model in classifying PNES and ES, paving the way for further advancements in the field and benefiting patients and healthcare practitioners in diagnosis and treatment

Cross-domain MLP and CNN Transfer Learning for Biological Signal Processing: EEG and EMG

In this work, we show the success of unsupervised transfer learning between Electroencephalographic (brainwave) classification and Electromyographic (muscular wave) domains with both MLP and CNN methods. To achieve this, signals are measured from both the brain and forearm muscles and EMG data is gathered from a 4-class gesture classification experiment via the Myo Armband, and a 3-class mental state EEG dataset is acquired via the Muse EEG Headband. A hyperheuristic multi-objective evolutionary search method is used to find the best network hyperparameters. We then use this optimised topology of deep neural network to classify both EMG and EEG signals, attaining results of 84.76% and 62.37% accuracy, respectively. Next, when pre-trained weights from the EMG classification model are used for initial distribution rather than random weight initialisation for EEG classification, 93.82%(+29.95) accuracy is reached. When EEG pre-trained weights are used for initial weight distribution for EMG, 85.12% (+0.36) accuracy is achieved. When the EMG network attempts to classify EEG, it outperforms the EEG network even without any training (+30.25% to 82.39% at epoch 0), and similarly the EEG network attempting to classify EMG data outperforms the EMG network (+2.38% at epoch 0). All transfer networks achieve higher pre-training abilities, curves, and asymptotes, indicating that knowledge transfer is possible between the two signal domains. In a second experiment with CNN transfer learning, the same datasets are projected as 2D images and the same learning process is carried out. In the CNN experiment, EMG to EEG transfer learning is found to be successful but not vice-versa, although EEG to EMG transfer learning did exhibit a higher starting classification accuracy. The significance of this work is due to the successful transfer of ability between models trained on two different biological signal domains, reducing the need for building more computationally complex models in future research