Major issues in Brain Computer Interfaces (BCIs) include low usability and
poor user performance. This paper tackles them by ensuring the users to be in a
state of immersion, control and motivation, called state of flow. Indeed, in
various disciplines, being in the state of flow was shown to improve
performances and learning. Hence, we intended to draw BCI users in a flow state
to improve both their subjective experience and their performances. In a Motor
Imagery BCI game, we manipulated flow in two ways: 1) by adapting the task
difficulty and 2) by using background music. Results showed that the difficulty
adaptation induced a higher flow state, however music had no effect. There was
a positive correlation between subjective flow scores and offline performance,
although the flow factors had no effect (adaptation) or negative effect (music)
on online performance. Overall, favouring the flow state seems a promising
approach for enhancing users' satisfaction, although its complexity requires
more thorough investigations
