Using Brain Painting at Home for 5 Years: Stability of the P300 During Prolonged BCI Usage by Two End-Users with ALS.

Brain painting (BP) is non-invasive electroencephalography (EEG) based Brain-Computer Interface (BCI) for creative expression based on a P300 matrix. The technology was transferred into a home setup for two patients with amyotrophic lateral sclerosis (ALS), who used the system for several years while being evaluated on performance and satisfaction. Holz and colleagues found that the use of BP increased quality of life. Additionally, they described that changes in the amplitude of the P300 ERPs could be observed between recalibrations of the BCI. In this paper, we quantified the evolution of the P300 peaks in the two BCI end-users (HP and JT). For HP, the P300 peak amplitude increased during 9 months, then progressively decreased for the following 51 months, but the BCI accuracy remained stable. JT’s P300 peak amplitude did not significantly decrease during 32 months that separated the calibrations. Yet, JT’s BCI accuracy declined which we may attribute to a decline in physical functioning due to ALS. Painters used online BCI for hundreds of hours (HP 755, JT 223) and both finished more than 50 named brain paintings. HP could use BP autonomously and regularly at home for 33 months without recalibration of the system, and JT for 10 months, suggesting the stability of P300 and SWLDA online classifiers in the long-term, and demonstrating the feasibility of having a P300 based system at home that requires few involvement of BCI experts.