Determining Mental State from EEG Signals Using Parallel Implementations of Neural Networks

Issue title: Applications Analysis

Article type: Research Article

Authors: ANDERSON, CHARLES W. | DEVULAPALLI, SAIKUMAR V. | STOLZ, ERIK A.

Affiliations: Department of Computer Science, Colorado State University, Fort Collins, CO 80523; E-mail: {anderson,devulapa}@cs.colostate.edu | Department of Electrical Engineering, Colorado State University, Fort Collins, CO 80523

Abstract: EEG analysis has played a key role in the modeling of the brain's cortical dynamics, but relatively little effort has been devoted to developing EEG as a limited means of communication. If several mental states can be reliably distinguished by recognizing patterns in EEG, then a paralyzed person could communicate to a device such as a wheelchair by composing sequences of these mental states. EEG pattern recognition is a difficult problem and hinges on the success of finding representations of the EEG signals in which the patterns can be distinguished. In this article, we report on a study comparing three EEG representations, the unprocessed signals, a reduced-dimensional representation using the Karhunen – Loève transform, and a frequency-based representation. Classification is performed with a two-layer neural network implemented on a CNAPS server (128 processor, SIMD architecture) by Adaptive Solutions, Inc. Execution time comparisons show over a hundred-fold speed up over a Sun Sparc 10. The best classification accuracy on untrained samples is 73% using the frequency-based representation.

Journal: Scientific Programming, vol. 4, no. 3, pp. 171-183, 1995