Restoring the sense of touch with a prosthetic hand through a brain interface
The human hand uses sensory feedback for dexterity as well as providing an emotional component. It would be desirable for a prosthetic hand to provide this feedback. Intracortical microstimulation (ICMS) of primary somatosensory cortex may be mimicked to convey information about the hand.
There are three main components:
- Location on hand: Signalling where to grasp. The test showed that localized ICMS elicits a relevant sensation in the hand.
- Pressure: To avoid crushing or dropping. Tests showed that ICMS amplitude changes convey different pressures, although it is unclear if the perception is entirely accurate.
- Timing: Contact signals the end of the reach-phase, stimulating the grasp-phase. The test showed that pressure feedback must be added to with phasic ICMS trains at the beginning and end of contact.
This method would involve evasive surgery; more trials are needed to validate human use. Modification may be needed for those whose somatosensory cortex has been interrupted (amputation etc.). >From: Tabot, et al., Proc Natl Acad Sci U S A. 110(2013) 18279-84. All rights reserved to the National Academy of Sciences.