BrainSpeak

In France, 300 000 people suffer from a strong speech disorder and more than 5 millions worldwide, often following brain strokes but also in case of severe tetraplegia, locked-in syndrome, neurodegenerative disease such as Amyotrophic Lateral Sclerosis or Parkinson’s disease, myopathies, or coma. The BrainSpeak project aims at developing the proof of concept of a complete paradigm to restore speech using a brain-computer interface (BCI). This speech BCI will be developed in patients undergoing a presurgical evaluation of their pharmaco-resistant epilepsy using intracranial recordings. Cortical signals will be recorded using high-density electrocorticographic and/or intracortical microelectrode arrays from motor speech areas, and decoded to control an artificial speech synthesizer in real time. The INSERM partner will implement a speech BCI clinical trial (for which a CPP approval and an ANSM authorization have recently been obtained) with CHU Grenoble in collaboration with GIPSA-Lab. To this end, we will characterize the cortical dynamics underlying speech production and imagination and decode these signals to predict overt and covert speech. Decoding will be first tested offline and then implemented online to allow subjects to control a speech synthesizer in real time. In parallel, we will carry out methodological developments to improve the BCI experimental chain. For this purpose, novel machine learning algorithms will be developed by GIPSA-Lab in collaboration with INSERM for better speech synthesis and cortical signal decoding. These algorithms will provide more intelligible speech synthesis and more efficient decoding methods adapted to the transcoding of neural recordings into speech features (articulatory or spectral trajectories). The speech BCI approach will be developed here as a proof of concept in patients having preserved brain areas and able to speak, in order to pave new routes for future speech rehabilitation in patients who cannot communicate verbally (e.g. locked-in people).