A somatotopic bidirectional hand prosthesis with transcutaneous electrical nerve stimulation based sensory feedback

Area of Science:

• Neuroscience
• Biomedical Engineering
• Rehabilitation Medicine

Background:

• Sensory feedback is crucial for effective prosthetic limb control, yet it is largely absent in current commercial prostheses.
• Implantable neural interfaces can restore touch but require surgery and have uncertain long-term viability.
• A non-invasive method is needed to provide somatotopic sensory feedback, mimicking natural touch perception.

Purpose of the Study:

• To develop and evaluate a non-invasive sensory feedback system for upper-limb amputees.
• To assess the feasibility of using transcutaneous electrical nerve stimulation (TENS) for prosthetic sensory restitution.
• To investigate the functional benefits of this non-invasive sensory feedback in prosthesis control.

Main Methods:

• Developed a non-invasive system using TENS to induce referred sensations in the phantom hand of amputees.
• Characterized the induced sensations in four amputees over a two-week period.
• Utilized electroencephalography (EEG) to confirm neural responses in relevant cortical areas.
• Integrated the TENS-based sensory feedback into a bidirectional prosthesis control system.

Main Results:

• TENS successfully induced referred sensations in the phantom hand, often perceived as paresthesia.
• The location of induced sensations corresponded to the median and ulnar nerve innervation regions.
• EEG recordings showed appropriate neural activity in cortical areas related to hand sensation.
• Amputees demonstrated high performance in functional tasks, including force discrimination, using the sensory feedback.

Conclusions:

• Non-invasive TENS can provide a viable somatotopic sensory feedback for prosthetic limbs.
• This approach offers a promising alternative to invasive methods, balancing sensation quality with reduced invasiveness.
• The developed system significantly enhanced functional capabilities for amputees using prosthetic devices.