OVERT SPEECH RETRIEVAL FROM NEUROMAGNETIC SIGNALS USING WAVELETS AND ARTIFICIAL NEURAL NETWORKS

Speech production involves the synchronization of neural activity between the speech centers of the brain and the oral-motor system, allowing for the conversion of thoughts into meaningful sounds. This hierarchical mechanism is hindered due to partial or complete paralysis of the articulators for patients suffering from locked-in-syndrome. These patients are in dire need of effective brain-communication interfaces (BCIs), which can at least provide a level of communication assistance. In this study, we tried to decode overt (loud) speech directly from the brain via non-invasive magnetoencephalography (MEG) signals to build the foundation for a faster, direct brain to text mapping BCI. A shallow Artificial Neural Network (ANN) was trained with wavelet features of the MEG signals for this objective. Experimental results show that a direct speech decoding is possible from MEG signals. Moreover, we found that the jaw motion and MEG signals may have complimentary information for speech decoding.