[FoRK] UI evolution
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
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 ) 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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