An EEG-based method for graded cursor control

Individuals were trained to modulate their EEGs in order to move a cursor on a video screen to intercept a moving target. EEG activity was recorded from the scalp over the central sulcus of the left hemisphere, and mu-rhythm amplitude was assessed three times per second by a fast Fourier transform. The cursor began at the midpoint of the right edge of the screen and moved up or down depending on mu-rhythm amplitude. A target of selected vertical length began at a random height on the left edge of the screen and moved horizontally across the screen in 8 sec. The subjects’ task was to move the cursor along the right edge of the screen so as to intercept the moving target. After several weeks of training, 3 of the 4 subjects were able to perform this task with significant success. On average, these 3 subjects reduced the vertical target-cursor distance to 54% of its initial value. These results indicate that the mu rhythm can be used to control graded cursor movement and are additional evidence that with further development it might provide a new means of communication and control for individuals with severe motor disabilities.