To advance BCI hardware, different types of materials and devices must be investigated to figure out which would work the most effectively while being cost-effective and high quality. The most critical component of the operation of non-invasive BCIs is the electroencephalogram (or EEG). The technology uses electrodes that attach to the scalp, which allow brain cells to communicate via electrical impulses.
In a spelling-based test conducted by Neumann and Birmbauer, they included a training phase with these five participants that included two different spelling modes: copy spelling and free spelling. The participants had to select a letter by producing positive SCP amplitude shifts or reject a letter by producing negative SCP amplitude shifts. After several training sessions, they found a much higher correct response rate compared to the first session (2003). This meant that, if the subjects attended training sessions, their accuracy would drastically increase.