Publications

Abstract—Evaluations of haptic feedback in myoelectric prostheses are generally limited to task performance outcomes, which
while necessary, fail to capture the mental effort of the user operating the prosthesis. Cognitive load is usually investigated with
reaction time metrics and secondary task accuracy, which are
indirect, and may not capture the time-varying nature of mental
effort. Here, we propose wearable, wireless functional near infrared
spectroscopy (fNIRS) neuroimaging to provide a continuous direct
assessment of operator mental effort during use of a prosthesis.
Utilizing fNIRS in a two-alternative forced-choice stiffness discrimination task, we asked participants to differentiate objects using
their natural hand, a (traditional) myoelectric prosthesis without
sensory feedback, and a myoelectric prosthesis with haptic (vibrotactile) feedback of grip force. Results showed that discrimination
accuracy and mental effort are optimal with the natural hand,
followed by the prosthesis featuring haptic feedback, and then
the traditional prosthesis, particularly for objects whose stiffness
were difficult to differentiate. This experiment highlights the utility
of haptic feedback in improving task performance and lowering
cognitive load for prosthesis use, and demonstrates the potential
for fNIRS to provide a robust measure of cognitive effort for other
human-in-the-loop systems.

@ARTICLE{9399397,  author={N. {Thomas} and G. {Ung} and H. {Ayaz} and J. D. {Brown}},  journal={IEEE Transactions on Human-Machine Systems},   title={Neurophysiological Evaluation of Haptic Feedback for Myoelectric Prostheses},   year={2021},  volume={},  number={},  pages={1-12},  doi={10.1109/THMS.2021.3066856}}

10.1109/THMS.2021.3066856