ENGR0011 Section: 14280
Group #R06
NEUROPROSTHETICS: RECOVERING LOST FEELINGS
Vineet Pradhan (vhp2@pitt.edu)
INTRODUCTION: WHAT IS
NEUROPROSTHETICS?
Neuroprosthetics-what does this complicated word mean? It
is the combining of the research on prosthetics with the
study of the brain and spinal cord. Moreover, it is also the
study and implantation of prosthetics in and around the brain
and spinal cord, so people can regain brain and nerve
functions they have lost due to severe injury or just simply
not being born with them. For many years now, people have
been studying, creating, and improving prosthetic arms, legs,
and other body parts. We have even come to a point where
people have been able to survive with artificial organs, i.e.
livers, lungs, and even hearts. The next step forward is
neuroprosthetics. If researchers can conquer this field, they
would be able to implant artificial parts in the brain to allow
people who can’t feel something, or don’t have control of
some body part, or even all their body parts, regain that
control. Researchers could also use neuroprosthetics to help
people who lack proprioception, which normally is a trait
that is overlooked by human beings. Because of the huge
potential benefits of neuroprosthetics, the research in this
field has grown greatly in the last few years. I have always
been interested in prosthetics, and my goal as an aspiring
bioengineer is to work in this field. Neuroprosthetics is a
completely different subject in the prosthetics world that I
find even more interesting because somehow being able to
manipulate the functions of the brain is truly amazing to me.
UNDERSTANDING PROPRIOCEPTION
According to princeton.edu, proprioception is the ability to
sense position and location and orientation and movement of
the body and its parts. In layman’s terms, because of
proprioception, we can touch our nose without looking for it
and blink our eyes without first trying to figure out where
the eyes are. Why is it important for researchers and doctors
to understand proprioception? If they can easily comprehend
this “sixth sense”, they might be able to manipulate it, which
would come in handy because there are many people who
lose this sense due to a spinal cord tumor, multiple sclerosis
(MS), or some other major brain or spinal cord injury.
Doctors and researchers could possibly make a device that
could allow people who lost this sense, regain it so they can
do what the majority of people can do without even thinking
hard. As a prospective bioengineering student, I believe that
researchers and doctors should continue to try to learn about
proprioception, and continue to attempt to develop
University of Pittsburgh, Swanson School of Engineering 1
Group: #R06
neuroprosthetics to help people whose “sixth sense” is either
weakened or nonexistent [10].
INJURIES TO THE BRAIN AND/OR SPINAL
CORD
As stated in the previous section, these neuroprosthetics
could allow people who have lost their “sixth sense” regain
it. How might people lose their “sixth sense”? An injury to
the brain or spinal cord, or in other words, any damage to a
part of the nervous system could cause this impairment. An
example of a treacherous instance where this has actually
happened was mentioned in Nature Magazine. They mention
a man named Ian Waterman, who lost his “sixth sense” due
to a flu-like virus that damaged his required sensory nerves
almost overnight. As the article states, “his muscles worked
perfectly, but he could not control them.” Waterman needed
something that could allow him to regain control of all of his
muscles. That is where the field of neuroprosthetics comes
into play. Slowly, after a long time of studying and trying
neuroprosthetics on Waterman, he was finally able to control
something. Researchers implanted 96 electrodes into his
motor cortex, the region of the brain that processes
information about movement. Then a cursor on a screen was
calibrated to his thoughts and the implanted electrodes so he
would be able to move it by just thinking about moving it.
He was successful in this neuroprosthetic experiment,
because he was able to the move a cursor with only his
thought [10]. This was a huge step forward for him because
it meant that he was indeed developing the ability that he
had lost that night. I feel as if this was the best example of
the potential neuroprosthetics has in the medical world.
Being able to move a cursor with his thought was a miracle
for Waterman. If neuroprosthetics are studied to a much
greater extent, its benefits can be shared by many people
who lack proprioception. The proprioception branch of
neuroprosthetics is only one way neuroprosthetics can be
used in one’s body and help someone. The other way is
directly affecting their muscles.
STIMULATING PARALYZED MUSCLES
Neuroprosthetics can not only help people regain control of
their nervous system, but they can also help muscles from
limbs regain the power to move. Rather than implanting a
whole new arm, or leg, neuroprosthetics allow a small
prosthetic in one’s body that needs “minimal maintenance”
and is “user-friendly” according to NeuroRehabilitation.
This kind of neuroprosthetic electrically stimulates people’s
Vineet Pradhan
paralyzed muscles so they can move again. The people that
would need this kind of neuroprosthetic would be the ones
that can feel their leg, or arm, but they cannot move it. They
know how to move it, but it won’t move. Not only can these
neuroprosthetics control limbs, they can also control things
like the bladder, assist in breathing, and bowel movements.
In an extremely severe case, where someone has lost their
limb and the nerves to access that limb, doctors could
potentially
combine
traditional
prosthetics
and
neuroprosthetics and provide a limb that has full feeling,
which would truly be remarkable. Developing this kind of
super artificial connection in one’s body is referred to as
“hybrid neuroprosthetics”.
concern, researchers have created a multilayer coating of
SiC and Parylene C. This has reduced the chance for nerve
tissue damage because both these substances provide the
device with a layer that is unreactive with anything around
it, so the metal or the material the substance is made of will
not react negatively with anything else in the body. This
multilayer coating also makes the device somewhat softer to
the outside, which provides protection for the nerve tissue
around it so it doesn’t get ruptured. If researchers are able to
eliminate this major danger, the neuroprosthetic field could
gain many more supporters and the knowledge would take
off [9]. Along with the chance of nervous system damage,
there is also chance for negative feedback from the immune
system if a neuroprosthetic is implanted.
HYBRID NEUROPROSTHETICS
Immune System Response
The IEEE Transactions on Biomedical Engineering says,
“the hybrid neuroprosthetic system is emerging as one of the
most innovative areas of robotics and engineering”. This is
because as I said earlier, being able to incorporate both
traditional prosthetics and neuroprosthetics in the same body
part is a big step forward in the medical world. A hybrid
neuroprosthetic can be classified with three criteria: level of
hybridness, level of augmentation, and level of connection to
the nervous system [3]. Level of hybridness is how
connected it is to the human body and whether it links the
artificial and natural systems together. Level of
augmentation is how powerful it is and how much it can do.
Level of connection to the nervous system is whether the
neuroprosthetic is connected to the peripheral nervous
system (PNS), the central nervous system (CNS), or both.
[3]. All of the hybrid prosthetics use electrical stimulation to
operate the way they are built. These many variations mean
that hybrid neuroprosthetics can help many people with
different types of problems or disorders. Throughout this
article there have only been remarkable concepts discussed,
but of course there are many challenges that researchers and
doctors have to overcome to make neuroprosthetics a viable
option for patients.
Whenever a foreign substance enters the body, the immune
system always decides whether the substance belongs or not.
Then it gives either positive or negative feedback based on
what it believes. If wires and percutaneous connectors are
implanted into someone’s body, one could only assume that
the body won’t like the face that they are present and will
react negatively [9]. This is the other big challenge doctors
and researchers face when talking about implanting
neuroprosthetics. This hurdle is probably bigger than the
nerve tissue damage one because this is something the
doctors would need to wait for some period of time to see
how the implanted device has affected the body, positively
or negatively [5].
ETHICAL COMMENTARY AND
CONCERNS
Critics of Neuroprosthetics
As with any major breakthrough with possible
complications, there are of course those critics who believe
the complications are far worse than the benefits. As
mentioned in previous sections, implanting a neuroprosthetic
device has the potential of damaging one’s nerve tissue. The
neuroprosthetic device could also result in a negative
response by the immune system. According to the first
section of the National Society of Professional Engineers
(NSPE)’s code of ethics, “Engineers shall hold paramount
the safety, health, and welfare of the public” [6]. This is the
main section of this code of ethics that critics are pointing to
when they say the benefits of neuroprosthetics are not worth
the risk. Although biomedical engineers are dealing with a
delicate part of the body with these neuroprosthetics, I
believe that these devices are indeed worth the risk, because
as research in this field improves, there will be less and less
risk associated with this field.
POSSIBLE COMPLICATIONS OF
NEUROPROSTHETICS
Damages to Nerve Tissues Due to Implantation of
Neuroprosthetics
Implanting anything into one’s body could cause negative
feedback from the body. People have to be especially careful
when manipulating the brain and nerve areas as well,
because one microscopic mistake could lead to a massive
problem for someone for the rest of their life. Damaging
nerve tissue when inserting and using these neuroprosthetics
has been one of the main concerns for researchers and
doctors who have chosen to study this subject. According to
the Nanomedicine Magazine, to attempt to combat this
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Vineet Pradhan
to increase the competence, prestige, and honor of the
biomedical engineering profession” [7]. Breakthroughs in
the neuroprosthetic field are definitely examples that
biomedical engineers should use to lead and motivate their
co-researchers and co-workers to achieve more.
Biomedical Engineering Research
The ultimate goal of the researchers should be to build these
neuroprosthetic devices with as less risk as possible, and
have these device be as safe as possible. The Biomedical
Engineering Society’s code of ethics has a whole section for
researchers. The first part of this section states that all
biomedical engineering researchers should “Comply fully
with legal, ethical, institutional, governmental, and other
applicable research guidelines, respecting the rights of and
exercising the responsibilities to human and animal subjects,
colleagues, the scientific community and the general public”
[7]. In simpler terms, this means that biomedical engineering
researchers should abide by all the rules that go along with
safety in the research laboratory and they should treat the
subjects they test their devices on in a humane manner. In
my opinion, this is the most important of the ethical codes
that biomedical engineering researchers should abide by
because safety of the subjects and safety of the people who
actually use the device is most important. This is especially
important when dealing with neuroprosthetics and the
nervous system. Since the brain, spinal cord, and nerves are
very delicate and could be manipulated easily, it is crucial
for researchers to maintain legality and respect the rights of
humans and animals, because they could potentially make a
small change in the system and make a huge difference in
the way someone thinks or feels. Another part of the
Biomedical Engineering Society’s code that pertains to
researchers states that all biomedical engineering researchers
should also “Publish and/or present properly credited results
of research accurately and clearly” [7]. This could be
considered the “common sense” part of the biomedical
engineering researchers’ code. Of course, if a biomedical
engineer should truthfully talk about his or her research
findings and explain what they have learned in a way that
everyone interested can understand it. Just as biomedical
researchers are constrained to these ethical laws, biomedical
engineers directly involved in the professional aspect of the
field also have their own ethics that they need to abide by.
NSPE’s Take On Ethics
The NSPE has a much broader view on ethics, since they
have to incorporate all different fields of engineering. But of
course there are many codes in the NSPE’s code of ethics
that pertain to biomedical engineering and more specifically,
the study and implantation of neuroprosthetics. One section
in their code states “Engineers shall perform services only in
the areas of their competence” [6]. This simply means that
biomedical engineers and neuroprosthetic researchers should
only be allowed to partake in neuroprosthetic studies if they
are qualified to do so. This assures that people who are not
as qualified and could produce partially erroneous results are
not allowed to take part in this research. This makes
neuroprosthetic research more official and will result in
better studies. Another section of the code of ethics put
forward by the NSPE says that “Engineers shall avoid
deceptive acts” [6]. While performing research, or building
neuroprosthetic devices, biomedical engineers should never
try to cover up a mistake to save time, or exaggerate a
finding to attempt to give them more credibility.
Wrap-up on Ethics
With every breakthrough comes controversy. The field of
neuroprosthetics is no different from any other
breakthrough. However, as long as biomedical engineers and
biomedical engineering researchers abide by the codes of
ethics put forth by the NSPE and Biomedical Engineering
Society, there will be little or no problem in the future with
these studies and devices. I hope that this field begins to lose
critics and gain much more supporters, so peoples’ lives can
be saved faster and they’ll have a much lower risk of
problems due to neuroprosthetics.
Biomedical Engineers’ Professional Obligations
STUDYING ETHICS AS A FRESHMAN
ENGINEER
According to the Biomedical Engineering Society’s code of
ethics, all biomedical engineers should “Use their
knowledge, skills, and abilities to enhance the safety, health,
and welfare of the public” [7]. This is almost exactly what it
says in the NSPE’s code of ethics. The fact that this is the
first statement in both the NSPE’s and the Biomedical
Engineering Society’s code of ethics means that it is
obviously important in the biomedical engineering and
engineering world. Relating to neuroprosthetics, this applies
in the sense that the studies they do and the devices they
make should better the health of the people that wish to have
that device implanted. The other “professional obligation”
according to this code of ethics states that all biomedical
engineers should “Strive by action, example, and influence
Researching and learning about the previously unknown
field of neuroprosthetics was definitely a great experience
for me. Researching the codes of ethics and connecting it
back to this field that I am newly interested in was also very
interesting for me to do. I however, do not believe that
learning and researching these things during my freshman
year is as useful as learning and researching these things as a
sophomore or junior would be. The main reason that I
believe this is I currently haven’t taken an official
bioengineering course yet, so right now I have no knowledge
of bioengineering at all. Although reading about
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Vineet Pradhan
neuroprosthetics was interesting, I feel that I would have
gotten more out of it if I had some bioengineering
knowledge before I actually did the research. There were
many articles that I skimmed that I think may have been
more interesting if I was able to fully comprehend them.
ADDITIONAL SOURCES
[9] F. Solzbacher, R. Harrison, R. Normann, H. Oppermann,
M. Klein, K. Koch (Sept. 2005). “Integrated neural
interfaces arrays for neuroprosthetic applications.”
Nanomedicine: Nanotechnology, Biology, and Medicine.
(Online Article).
http://www.sciencedirect.com.pitt.idm.oclc.org/
[10] A. Abbott. (Jul. 2006). “Neuroprosthetics: In Search of
the Sixth Sense.” Nature. (Print Article).
http://search.proquest.com.pitt.idm.oclc.org/
FINAL THOUGHTS
The field of neuroprosthetics has opened up a whole new
world of artificiality in the biomedical engineering and
medical worlds. I believe that this issue deserves much
attention because of the benefits it has. These breakthroughs
could potentially provide people who can’t feel or access a
limb to be able to use an artificial limb with artificial nerves
and live a normal life. I hope to possibly take part in
research in this field because I would love to help in the
advancements of a field with such great potential.
ACKNOWLEDGEMENTS
I would like to thank all of the authors of the articles that
helped contribute to this article.
REFERENCES
[1] N. Bhadra, J. Chae. (2009). “Implantable
Neuroprosthetic
Techonology.”
NeuroRehabiltation.
(Online Article).
http://web.ebscohost.com.pitt.idm.oclc.org/
[2] J. Del R. Millan. (May-June 2009). “Neural
Engineering: EPFL Center for Neuroprosthetics.”
Engineering in Medicine and Biology Magazine. (Online
Article).
http://ieeexplore.ieee.org.pitt.idm.oclc.org/
[3] S. Micera. J. Carmena. (Jan. 2009). “Developing the
Next Generation of Hybrid Neuroprosthetic Systems.”
IEEE Transactions on Biomedical Engineering. (Online
Article).
http://ieeexplore.ieee.org.pitt.idm.oclc.org/he
[4] V. Sharma. (Feb 2010). “Bidirectional Telemetry
Controller
for
Neuroprosthetic
Devices.”
IEEE
Transactions on Neural Systems and Rehabilitation
Engineering. (Online Article).
http://ieeexplore.ieee.org.pitt.idm.oclc.org/
[5] P. Musienko. (Nov. 2009). “Combinatory Electrical and
Pharmacological Neuroprosthetic Interfaces to Regain
Motor Function after Spinal Cord Injury.” IEEE
Transactions on Biomedical Engineering. (Online Article).
http://ieeexplore.ieee.org.pitt.idm.oclc.org/
[6]“NSPE Code of Ethics for Engineers.” NSPE. (Online
Article).
http://www.nspe.org/
[7] Biomedical Engineering Code of Ethics.” Biomedical
Engineering Society. (Online Article).
http://www.bmes.org/
[8] (May 2012). “The Neurodevice 2012 Report:
Neuroprosthetics,
Neuromodulation,
Neurosurgery,
Neurovascular
Intervention
and
Neurosoftware.”
NeuroInsights. (Online Article).
http://www.lexisnexis.com/
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