Devices

Two 96-channel intracortical arrays in the motor cortex of a 52-year-old with tetraplegia, used to control an anthropomorphic prosthetic limb in seven dimensions. 91.6% success on reaching tasks after 13 weeks. The Lancet, February 2013.

Device — Intracortical

7 degree-of-freedom neuroprosthetic arm (Collinger, 2013)

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robotic arm · 7D control · intracortical · tetraplegia · Modular Prosthetic Limb · academic · human

7 degree-of-freedom neuroprosthetic arm (Collinger, 2013)

One-line verdict: A person with tetraplegia controlled an anthropomorphic prosthetic limb in seven dimensions, including grasp, and improved at it over 13 weeks.

Quick tags: Recording · Intracortical · Human · Published 16 February 2013 (The Lancet)

Overview

What it is: Two 96-channel intracortical microelectrodes were implanted in the motor cortex of a 52-year-old individual with tetraplegia. Over 13 weeks of brain-machine-interface training, the participant controlled a prosthetic limb with seven degrees of freedom: three-dimensional translation, three-dimensional orientation and one-dimensional grasping. The limb was the Modular Prosthetic Limb from Johns Hopkins University Applied Physics Laboratory.

Results (as reported): The participant moved the limb freely in the 3D workspace on the second day of training. After 13 weeks, seven-dimensional movements were routine. Mean success on target-based reaching tasks was 91.6% (SD 4.4) against a median chance level of 6.2%. Mean completion time fell from 148 s to 112 s and path efficiency rose from 0.30 to 0.38. The participant also made reach and grasp movements that produced clinically significant gains on upper limb function tests. No adverse events were reported.

Why it matters: The paper says earlier human studies had shown 3D translation plus an on/off grasp. This added orientation and a continuous grasp dimension in one participant.

Limits: One participant. The paper notes that computer-assisted stabilizing was used until week 10 and that the success rate above is from the last two weeks without assistance.

Spec Card Grid

Identity

  • Paper: “High-performance neuroprosthetic control by an individual with tetraplegia,” The Lancet 381(9866):557-564, 16 February 2013
  • Registration: ClinicalTrials.gov NCT01364480
  • Participant: one, age 52

Hardware

  • Implants: two 96-channel intracortical microelectrode arrays, motor cortex
  • Effector: Modular Prosthetic Limb (Johns Hopkins University Applied Physics Laboratory)

Results

  • Control: 7 degrees of freedom (3D translation, 3D orientation, 1D grasp)
  • Training: 13 weeks, 34 sessions
  • Success rate: 91.6% vs 6.2% chance

Evidence and limits

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

References