Optimizing P300-speller sequences by RIP-ping groups apart

Eoin M. Thomas 1 Maureen Clerc 1 Alexandra Carpentier 2 Emmanuel Daucé 3 Dieter Devlaminck 1 Rémi Munos 2
1 ATHENA - Computational Imaging of the Central Nervous System
CRISAM - Inria Sophia Antipolis - Méditerranée
2 SEQUEL - Sequential Learning
LIFL - Laboratoire d'Informatique Fondamentale de Lille, LAGIS - Laboratoire d'Automatique, Génie Informatique et Signal, Inria Lille - Nord Europe
Abstract : So far P300-speller design has put very little emphasis on the design of optimized flash patterns, a surprising fact given the importance of the sequence of flashes on the selection outcome. Previous work in this domain has consisted in studying consecutive flashes, to prevent the same letter or its neighbors from flashing consecutively. To this effect, the flashing letters form more random groups than the original row-column sequences for the P300 paradigm, but the groups remain fixed across repetitions. This has several important consequences, among which a lack of discrepancy between the scores of the different letters. The new approach proposed in this paper accumulates evidence for individual elements, and optimizes the sequences by relaxing the constraint that letters should belong to fixed groups across repetitions. The method is inspired by the theory of Restricted Isometry Property matrices in Compressed Sensing, and it can be applied to any display grid size, and for any target flash frequency. This leads to P300 sequences which are shown here to perform significantly better than the state of the art, in simulations and online tests.
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https://hal.inria.fr/hal-00907781
Contributor : Maureen Clerc <>
Submitted on : Thursday, November 21, 2013 - 5:16:14 PM
Last modification on : Thursday, February 21, 2019 - 10:52:49 AM
Long-term archiving on : Saturday, February 22, 2014 - 4:42:25 AM

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  • HAL Id : hal-00907781, version 1

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Eoin M. Thomas, Maureen Clerc, Alexandra Carpentier, Emmanuel Daucé, Dieter Devlaminck, et al.. Optimizing P300-speller sequences by RIP-ping groups apart. IEEE/EMBS 6th international conference on neural engineering (2013), IEEE/EMBS, Nov 2013, San Diego, United States. ⟨hal-00907781⟩

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