Classification effects of real and imaginary movement selective attention tasks on a P300-based brain–computer interface

Abstract

Brain-computer interfaces (BCIs) rely on various electroencephalography methodologies that allow the user to convey their desired control to the machine. Common approaches include the use of event-related potentials (ERPs) such as the P300 and modulation of the beta and mu rhythms. All of these methods have their benefits and drawbacks. In this paper, three different selective attention tasks were tested in conjunction with a P300-based protocol (i.e. the standard counting of target stimuli as well as the conduction of real and imaginary movements in sync with the target stimuli). The three tasks were performed by a total of 10 participants, with the majority (7 out of 10) of the participants having never before participated in imaginary movement BCI experiments. Channels and methods used were optimized for the P300 ERP and no sensory-motor rhythms were explicitly used. The classifier used was a simple Fisher's linear discriminant. Results were encouraging, showing that on average the imaginary movement achieved a P300 versus No-P300 classification accuracy of 84.53%. In comparison, mental counting, the standard selective attention task used in previous studies, achieved 78.9% and real movement 90.3%. Furthermore, multiple trial classification results were recorded and compared, with real movement reaching 99.5% accuracy after four trials (12.8 s), imaginary movement reaching 99.5% accuracy after five trials (16 s) and counting reaching 98.2% accuracy after ten trials (32 s).

Novel sequential protocols for a ERP based BCI mouse

“…The Imaginary Movement results were disappointing, especially when compared to the results obtained in [16]. Of course this experimental protocol differed considerably from the one used in [16].…”

“…The Imaginary Movement results were disappointing, especially when compared to the results obtained in [16]. Of course this experimental protocol differed considerably from the one used in [16]. For instance in the previous experiment subjects had to carry out 8 direction epochs of real movement before they carried out any imaginary movement recordings.…”

“…The first protocol (Single Colour) was expected to produce a visual evoked potential (VEP) when the target flashed. The second protocol (Imaginary Movement), inspired by previous work [16], was expected to generate a VEP as well as a motor related potentials. The third and final protocol named the Random Colour was expected to generate a VEP response as well as a P300.…”

Brain-actuated Control of Robot Navigation

“…Motor imagery can be used with any timing protocol. It can be used by itself in a cue based approach, in a self-paced system, or used in combination with the P300 approach discussed below (as in Salvaris & Sepulveda, 2010), although the latter has not been applied to robot navigation. One of the limitations of MI-based BCIs for robot control is that usually a few seconds of EEG data are needed for each control decision and for the motor cortex to fully return to a neutral state.…”

“…hand movements), or ii) the computer makes decisions based on the user's brain's involuntary response to a particular stimulus (e.g., flashing of an object on a computer screen), although both approaches have been combined recently as well (Salvaris & Sepulveda, 2010).…”