  Individuals living with paralysis or amputation can operate robotic
prostheses using input signals based on their intent or attempt to move.
Because sensory function is lost or diminished in these individuals, haptic
feedback must be non-collocated. The intracortical brain computer interface
(iBCI) has enabled a variety of neural prostheses for people with paralysis. An
important attribute of the iBCI is that its input signal contains
signal-independent noise. To understand the effects of signal-independent noise
on a system with non-collocated haptic feedback and inform iBCI-based
prostheses control strategies, we conducted an experiment with a conventional
haptic interface as a proxy for the iBCI. Able-bodied users were tasked with
locating an indentation within a virtual environment using input from their
right hand. Non-collocated haptic feedback of the interaction forces in the
virtual environment was augmented with noise of three different magnitudes and
simultaneously rendered on users' left hands. We found increases in distance
error of the guess of the indentation location, mean time per trial, mean peak
absolute displacement and speed of tool movements during localization for the
highest noise level compared to the other two levels. The findings suggest that
users have a threshold of disturbance rejection and that they attempt to
increase their signal-to-noise ratio through their exploratory actions.
