[FoRK] UI evolution

Eugen Leitl eugen at leitl.org
Sat Feb 16 12:28:34 PST 2013

On Sat, Feb 16, 2013 at 07:58:19AM -0800, Joseph S. Barrera III wrote:

> So the input device of the future will be a Dance Dance Revolution platform?

Too much mass for motorics. If anything, eye tracking and speech (subvocal

Long-term, something like

High-performance neuroprosthetic control by an individual 
with tetraplegia
Jennifer L Collinger, Brian Wodlinger, John E Downey, Wei Wang, Elizabeth C Tyler-Kabara, Douglas J Weber, Angus J C McMorland, Meel Velliste, 
Michael L Boninger, Andrew B Schwartz
Background Paralysis or amputation of an arm results in the loss of the ability to orient the hand and grasp, manipulate, 
and carry objects, functions that are essential for activities of daily living. Brain–machine interfaces could provide a 
solution to restoring many of these lost functions. We therefore tested whether an individual with tetraplegia could 
rapidly achieve neurological control of a high-performance prosthetic limb using this type of an interface.
Methods We implanted two 96-channel intracortical microelectrodes in the motor cortex of a 52-year-old individual 
with tetraplegia. Brain–machine-interface training was done for 13 weeks with the goal of controlling an 
anthropomorphic prosthetic limb with seven degrees of freedom (three-dimensional translation, three-dimensional 
orientation, one-dimensional grasping). The participant’s ability to control the prosthetic limb was assessed with 
clinical measures of upper limb function. This study is registered with ClinicalTrials.gov, NCT01364480.
Findings The participant was able to move the prosthetic limb freely in the three-dimensional workspace on the 
second day of training. After 13 weeks, robust seven-dimensional movements were performed routinely. Mean 
success rate on target-based reaching tasks was 91·6% (SD 4·4) versus median chance level 6·2% (95% CI 2·0–15·3). 
Improvements were seen in completion time (decreased from a mean of 148 s [SD 60] to 112 s [6]) and path effi  ciency 
(increased from 0·30 [0·04] to 0·38 [0·02]). The participant was also able to use the prosthetic limb to do skilful and 
coordinated reach and grasp movements that resulted in clinically signifi cant gains in tests of upper limb function. 
No adverse events were reported.
Interpretation With continued development of neuroprosthetic limbs, individuals with long-term paralysis could 
recover the natural and intuitive command signals for hand placement, orientation, and reaching, allowing them to 
perform activities of daily living.
Funding Defense Advanced Research Projects Agency, National Institutes of Health, Department of Veterans Aff airs, 
and UPMC Rehabilitation Institute.
Brain–machine interfaces transform neural activity 
into control signals for an external device. Functional 
elec trical stimulators, exoskeletons, and sophisticated 
prosthetic limbs are being developed with the goal of 
restoring natural function. For many activities of daily 
living, an individual needs to be able to position the hand 
in space, orient the palm, and grasp an object. These 
hand move ments are normally smoothly co ordinated 
and follow the general principles of natural movement.
Ideally a brain–machine interface will translate neural 
activity into control of an external device with the 
capability of producing natural move ments in accordance 
with the general principles.
The natural features of movement have been captured 
in recordings of motor cortical neural activity using intracortical microelectrodes in a study in non-human primates.
 In other animal studies, a robot arm was 
con trolled in four dimensions for self-feeding tasks
in seven dimensions for orien tation and grasping.
cortical activity has also been used to electrically activate 
paralysed muscles of the upper limb.
 Results of studies 
in people have shown three-dimensional translational 
 and control over a single grasping dimension.
 We therefore tested whether an individual with 
tetra plegia could rapidly achieve control of a state-of-theart anthropomorphic prosthetic limb (modular prosthetic 
limb [MPL], Johns Hopkins University, Applied Physics 
Laboratory, Baltimore, MD, USA).
The participant was a 52-year-old woman who was 
diagnosed with spinocerebellar degeneration 13 years 
before she took part in this study. Thorough chart review 
and discussions with her neurologist showed no indication 
of cerebellar involvement. The participant’s injury was 
motor complete with manual muscle test scores 0 of 5 for 
the upper limb.
 Physical examination showed that she 
had generally intact sensation with some hypersensitivity.
This study was approved by the institutional review 
boards at the University of Pittsburgh (Pittsburgh, PA, 
USA) and the Space and Naval Warfare Systems Center 
Pacifi c (San Diego, CA, USA). We obtained verbal informed 
consent from the woman before her partici pation in 
the study; consent was signed by her legal representative.

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