Functional near infrared spectroscopy (NIRS) is a relatively new technique complimentary to EEG for the development of brain-computer interfaces (BCIs). NIRS-based systems for detecting various cognitive and affective states such as mental and emotional stress have already been demonstrated in a range of adaptive human–computer interaction (HCI) applications.
@article{straitscheutz14frontiers,
title={What we can and cannot (yet) do with functional near infrared spectroscopy},
author={Megan Strait and Matthias Scheutz},
year={2014},
journal={Frontiers in Neuroscience},
volume={8},
pages={117}
url={https://hrilab.tufts.edu/publications/straitscheutz14frontiers.pdf}
doi={10.3389/fnins.2014.00117}
}