In short, they've put sensors of el. activity on pectoral muscles,
which send commands to muscles on the prosthetic arm. The patient
learns to control visual perceptions of arm movements by contracting
smaller muscles in the pectoral area (my interpretation, they did all
that from a motor command paradigm). The interesting phenomenon is the
appearance of sensations of touching in the prosthetic arm, even
though there are no pressure sensors on it.
My first question is - how is this happening? Is it similar to curing
phantom limb pain (the Ramachandran mirror box)?
The second question is - could PCT be used to improve on design of the
limb? My thinking is, keep pectoral muscles controlling arm muscles,
but add pressure sensors on fingers and tension sensors on 'tendons'.
Then project them somewhere on skin (on the back?) as vibro-tactile or
electrical stimuli*. For example, the frequency of el. stimuli on the
skin would be proportional to the stretch of a tendon, or to the
pressure on the pressure sensor on fingers.
That way, patients would learn to control kinestetic perceptions of
arm movements, instead of just visual, and they could "realy" feel
what they touch. Might lead to a more efficient learning proces and
better control?
-----Original Message-----
From: Control Systems Group Network (CSGnet)
[mailto:CSGNET@LISTSERV.ILLINOIS.EDU] On Behalf Of Adam Matic
Sent: Wednesday, October 26, 2011 5:05 PM
To: CSGNET@LISTSERV.ILLINOIS.EDU
Subject: Prosthetic arms
I just saw a presentation on TED of a new form of prosthetic arms that
"feel" and I've got a question.
In short, they've put sensors of el. activity on pectoral muscles,
which send commands to muscles on the prosthetic arm. The patient
learns to control visual perceptions of arm movements by contracting
smaller muscles in the pectoral area (my interpretation, they did all
that from a motor command paradigm). The interesting phenomenon is the
appearance of sensations of touching in the prosthetic arm, even
though there are no pressure sensors on it.
My first question is - how is this happening? Is it similar to curing
phantom limb pain (the Ramachandran mirror box)?
The second question is - could PCT be used to improve on design of the
limb? My thinking is, keep pectoral muscles controlling arm muscles,
but add pressure sensors on fingers and tension sensors on 'tendons'.
Then project them somewhere on skin (on the back?) as vibro-tactile or
electrical stimuli*. For example, the frequency of el. stimuli on the
skin would be proportional to the stretch of a tendon, or to the
pressure on the pressure sensor on fingers.
That way, patients would learn to control kinestetic perceptions of
arm movements, instead of just visual, and they could "realy" feel
what they touch. Might lead to a more efficient learning proces and
better control?
Right! I was fascinated when I read about it a few years ago, but
didn't know what to make of it. I haven't seen stretch sensing or
pressure sensing substitution yet.
Best, Adam
···
On Thu, Oct 27, 2011 at 1:30 AM, Ted Cloak <tcloak@unm.edu> wrote:
Re your second question: Paul Bach y Rita called this "sensory
substitution":
