Decoding electroencephalographic signals for direction in brain-computer interface using echo state network and Gaussian readouts

Noninvasive brain-computer interfaces (BCI) for movement control via an electroencephalogram (EEG) have been extensively investigated. However, most previous studies decoded user intention for movement directions based on sensorimotor rhythms during motor imagery. BCI systems based on mapping imagery movement of body parts (e.g., left or right hands) to movement directions (left or right directional movement of a machine or cursor) are less intuitive and less convenient due to the complex training procedures. Thus, direct decoding methods for detecting user intention about movement directions are urgently needed. Here, we describe a novel direct decoding method for user intention about the movement directions using the echo state network and Gaussian readouts. Importantly parameters in the network were optimized using the genetic algorithm method to achieve better decoding performance. We tested the decoding performance of this method with four healthy subjects and an inexpensive wireless EEG system containing 14 channels and then compared the performance outcome with that of a conventional machine learning method. We showed that this decoding method successfully classified eight directions of intended movement (approximately 95% of an accuracy). We suggest that the echo state network and Gaussian readouts can be a useful decoding method to directly read user intention of movement directions even using an inexpensive and portable EEG system. •The echo state network and Gaussian readouts decode user intention of movement directions using the electroencephalography.•Intended movement directions can be directly decoded without motor imagery of body movement.•Echo state network can successfully read user intention of movement direction even using low-cost EEG systems.•Genetic algorithms are useful for optimizing the parameters of echo state network decoders.