Figure 2.
Questionnaire responses of 58 participants to statements regarding training session and spelling interface. Answers were given on a 1–7 Likert scale. The numbers in the bars indicate the absolute numbers of participants that gave the respective rating. (a) Post-training (prior to the on-line experiments) questionnaire related to the stimulus presentation. (b) Post-spelling questionnaire related to the stimulus presentation. (c) Post-spelling questionnaire related to the GUI design. (d) Post-spelling questionnaire related to the overall BCI performance.