They provide signals of lower noise and higher
selectivity than non-invasive BCIs, which record neural signals
from the scalp. Most non-invasive BCIs are based on electroencephalography
(EEG). While known to be susceptible to
noise and signal distortion, EEG signals are easily measurable.
In addition, EEG-based BCIs have relatively low cost and
low risk, which makes them the most widely used BCI
devices