From Restoration to Augmentation: New Approaches to Haptic Feedback for Artificial Limbs.

Haptic feedback is essential for precise motor control, making its integration into artificial limbs a critical design challenge. Current approaches to restoring lost tactile input in patients have focused on interfacing with somatosensory pathways at the brain, nerve, or skin level, achieving partial restoration. However, augmentative artificial limbs, devices that provide novel movement capabilities beyond the biological body, pose unique challenges. These limbs lack dedicated sensory pathways, raising fundamental questions about how to deliver tactile feedback for these devices without disrupting existing somatosensory function. A promising direction lies in exploiting intrinsic tactile feedback, which emerges naturally at the interface between wearable devices and the body. When an artificial limb moves or interacts with objects, the skin detects rich tactile cues transmitted through this interface. Amplifying and refining this intrinsic feedback, via materials optimized for transmission of tactile signals and wearable designs, could enable more intuitive and interpretable haptic feedback for augmentative limbs. This approach offers a pathway toward enhancing embodiment and motor control of augmentative artificial limbs.