Project 2012: Unspoken Speech Detection Using a Brain-Computer Interface

 

 

 

 

 

Hypothesis:

 It is hypothesized that the letters of the alphabet can be accurately classified using non-invasive EEG by a combination of signal enhancement, feature extraction and post-processing algorithms and the use of a novel classification method.  Letters within words imagined by the user as a series of musical notes at a specific cadence will be detected more accurately and more quickly than by the current non-invasive EEG P-300 speller technique.

 

Purpose:

·        To enable unspoken communication through a non-invasive EEG device.

·        Use musical patterns and cadence associated with each letter of the alphabet in order to speed up recognition vs. the traditional P300 Speller system.

·        A quicker speller system would enable locked-in patients (non-mobile people such as Dr. Stephen Hawking) the ability to communicate more thoroughly.

 

Procedure: 

·      Electrodes are attached to the heads of subjects at locations Fz, Cz, Pz, Oz, P3, P4 using the International 10-20 System.

·      Training Phase:  Subjects listen to a sound file containing 3 notes and one space during a 2 second period.  Each of these patterns is specific to a letter (A, F, T, E, R).  For the 2 seconds immediately after this, they “think” of the same pattern.  Their brainwaves are recorded. Subjects are encouraged to think of the tones in the same cadence and pattern with which they are heard.  Note that each subject is given two dry runs where the process occurs, but no readings are taken.

·      After the first session, the subjects take a break.  During this time, their brain recordings are trained using an LDA Classifier and a Bayes Algorithm.

·      Real-time Phase:  During a second session, the subjects are presented with a series of tones, each set representing on letter in the work “AFTER.”  They are played the correct tones for before each letter and system classifies it in real time.  If it is classified correctly, the tones for the next letter are presented.  If not, the subject repeats the last letter.

·        The process continues until all 5 letters in the word AFTER are correctly identified in the correct order.  The time taken is recorded.