Why standard brain-computer interface (BCI) training protocols should be changed: An experimental study

Camille Jeunet, Emilie Jahanpour, Fabien Lotte
J. Neural Eng.. 2016-05-11; 13(3): 036024
DOI: 10.1088/1741-2560/13/3/036024

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Jeunet C(1), Jahanpour E, Lotte F.

Author information:
(1)University of Bordeaux-Bordeaux, France-Laboratoire Handicap & Système
Nerveux. Inria Bordeaux Sud-Ouest-Talence, France-Project-Team Potioc.

OBJECTIVE: While promising, electroencephaloraphy based brain-computer
interfaces (BCIs) are barely used due to their lack of reliability: 15% to 30%
of users are unable to control a BCI. Standard training protocols may be partly
responsible as they do not satisfy recommendations from psychology. Our main
objective was to determine in practice to what extent standard training
protocols impact users’ motor imagery based BCI (MI-BCI) control performance.
APPROACH: We performed two experiments. The first consisted in evaluating the
efficiency of a standard BCI training protocol for the acquisition of non-BCI
related skills in a BCI-free context, which enabled us to rule out the possible
impact of BCIs on the training outcome. Thus, participants (N = 54) were asked
to perform simple motor tasks. The second experiment was aimed at measuring the
correlations between motor tasks and MI-BCI performance. The ten best and ten
worst performers of the first study were recruited for an MI-BCI experiment
during which they had to learn to perform two MI tasks. We also assessed users’
spatial ability and pre-training μ rhythm amplitude, as both have been related
to MI-BCI performance in the literature.
MAIN RESULTS: Around 17% of the participants were unable to learn to perform the
motor tasks, which is close to the BCI illiteracy rate. This suggests that
standard training protocols are suboptimal for skill teaching. No correlation
was found between motor tasks and MI-BCI performance. However, spatial ability
played an important role in MI-BCI performance. In addition, once the spatial
ability covariable had been controlled for, using an ANCOVA, it appeared that
participants who faced difficulty during the first experiment improved during
the second while the others did not.
SIGNIFICANCE: These studies suggest that (1) standard MI-BCI training protocols
are suboptimal for skill teaching, (2) spatial ability is confirmed as impacting
on MI-BCI performance, and (3) when faced with difficult pre-training, subjects
seemed to explore more strategies and therefore learn better.