Devices

Two intracortical arrays in motor cortex control a robotic arm while two in somatosensory cortex evoke touch by microstimulation. Trial times on a clinical upper-limb test fell by half, from a median 20.9 s to 10.2 s. Science, 1 May 2021.

Device — Intracortical

Bidirectional BCI with tactile feedback (Flesher, 2021)

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bidirectional BCI · intracortical microstimulation · somatosensory cortex · tactile feedback · robotic arm · tetraplegia · academic · human

Bidirectional BCI with tactile feedback (Flesher, 2021)

One-line verdict: Adding touch halved the time a robotic arm took to do the same task. Vision alone is a poor channel for grasping.

Quick tags: Recording and stimulation · Intracortical · Human · Published 1 May 2021 (Science 372:831-836)

Overview

What it is: A bidirectional BCI that records neural activity from motor cortex to control a prosthetic arm, and generates tactile sensations through intracortical microstimulation of somatosensory cortex. The study was run under an FDA investigational device exemption and is registered as NCT01894802.

Implant: Two microelectrode arrays with 88 wired electrodes were implanted in the hand and arm region of motor cortex to decode movement intent. Two more arrays with 32 wired electrodes were implanted in area 1, a cutaneous region of somatosensory cortex. Stimulation evoked sensations in the palm and fingers of the participant’s right hand, which he described as cutaneous.

Result (as reported): The participant, a person with tetraplegia, cut trial times on a clinical upper-limb assessment in half, from a median 20.9 s to 10.2 s. The gain came mainly from less time spent attempting to grasp objects. The authors say this shows that mimicking known biological control principles brings task performance closer to healthy human ability.

Limits: One participant.

Spec Card Grid

Identity

  • Paper: “A brain-computer interface that evokes tactile sensations improves robotic arm control,” Science, 1 May 2021, 372(6544):831-836
  • Registry: NCT01894802, FDA IDE

Architecture

  • Motor cortex: two arrays, 88 wired electrodes (record)
  • Somatosensory cortex (area 1): two arrays, 32 wired electrodes (stimulate)
  • Evoked sensation location: palm and fingers of the right hand

Results

  • Median trial time: 20.9 s to 10.2 s

Evidence and limits

  • Not covered here: array model and dimensions; no 3D model yet

References