Research

A binary method for simple and accurate two-dimensional cursor control from EEG with minimal subject training

Turan A Kayagil^1,2,3 , Ou Bai^1,4 , Craig S Henriquez² , Peter Lin¹ , Stephen J Furlani¹ , Sherry Vorbach¹ and Mark Hallett¹

¹  National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA

²  Duke University Department of Biomedical Engineering, Durham, NC 27708, USA

³  Georgetown University School of Medicine, Washington, DC 20057, USA

⁴  Virginia Commonwealth University Department of Biomedical Engineering, Richmond, VA 23284, USA

author email corresponding author email

Journal of NeuroEngineering and Rehabilitation 2009, 6:14doi:10.1186/1743-0003-6-14

Published:	6 May 2009

Abstract

Background

Brain-computer interfaces (BCI) use electroencephalography (EEG) to interpret user intention and control an output device accordingly. We describe a novel BCI method to use a signal from five EEG channels (comprising one primary channel with four additional channels used to calculate its Laplacian derivation) to provide two-dimensional (2-D) control of a cursor on a computer screen, with simple threshold-based binary classification of band power readings taken over pre-defined time windows during subject hand movement.

Methods

We tested the paradigm with four healthy subjects, none of whom had prior BCI experience. Each subject played a game wherein he or she attempted to move a cursor to a target within a grid while avoiding a trap. We also present supplementary results including one healthy subject using motor imagery, one primary lateral sclerosis (PLS) patient, and one healthy subject using a single EEG channel without Laplacian derivation.

Results

For the four healthy subjects using real hand movement, the system provided accurate cursor control with little or no required user training. The average accuracy of the cursor movement was 86.1% (SD 9.8%), which is significantly better than chance (p = 0.0015). The best subject achieved a control accuracy of 96%, with only one incorrect bit classification out of 47. The supplementary results showed that control can be achieved under the respective experimental conditions, but with reduced accuracy.

Conclusion

The binary method provides naïve subjects with real-time control of a cursor in 2-D using dichotomous classification of synchronous EEG band power readings from a small number of channels during hand movement. The primary strengths of our method are simplicity of hardware and software, and high accuracy when used by untrained subjects.