A Communication Aid utilizing Event Related brain Potentials

Abstract

This paper describes the development of Communication Aid for Amyotrophic Lateral Sclenosis (ALS) patients utilising the Event-Related brain Potential (ERP). ERPs are recorded from the subject during word discrimination tasks. For the visual stimulus of task, the 25 words which are arranged as a 5×5 matrix form are used. Raws and columns of the matrix are repeatedly flashed at randam on a CRT screen for 300[ms] with a period of 500[ms]. The subject focuses attention successively on a word be wishes to communicate. He is ordered to count the word that is the target stimulus. When the raws or columns containing the chosen word are flashed, a P300 is elicited. The P300 components of filtered and averaged ERP waveforms are successfully obtained from the target trials. Results clearly show that the P300 component can be used to detect the attention of the subject without any physical actions and can be used as a human-interface of the Communication Aids.