Neural Signal Based Control of the Dasher Writing System

Integration of the Dasher text-entry program with a brain-computer interface (BCI) system may give individuals with severe motor disabilities the ability to write using their neural signals. Five able-bodied participants previously trained to control their neural signals using motor imagery in an electroencephalogram-based BCI study were trained to control the Dasher program using similar methods. The time to write simple phrases in Dasher using BCI and standard mouse inputs were compared. To compare with existing technology, four disabled participants wrote the same phrases using their own augmentative communication input. The time to input phrases with Dasher-BCI was greater than that for Dasher-mouse and other alternative inputs. However, as Dasher is optimized for BCI control, it will become increasingly useful for people with severe motor and speech disabilities.

I. Introduction

Brain-computer interface (BCI) technology, which links neural signal based commands to computer based outputs, has advanced significantly over the past decade. The BCI research community aims to give people with motor disabilities the ability to use their neural signals to control devices ranging from computers to wheelchairs to prosthetic limbs. A major advantage of BCIs over other augmentative communication methods is its independence from muscle movement, which is required for all other devices. Many BCI studies have demonstrated that people can move a computer cursor to a target using neural signals collected from the scalp (electroencephalogram - EEG) [1]–[3], surface of the brain (electrocorticogram - ECoG) [4], [5], or within the brain (local field potential and action potential recordings) [6], [7]. This is typically accomplished by training the user to modulate their neural signals by performing motor imagery [1], [4], [5], [8]. However, with few exceptions [9], [10], even very simple computer based applications controlled with neural signals are not available for people with motor disabilities.