Katherine Dunkelberger

Katherine Dunkelberger

Disclaimer—This paper partially fulfills a writing requirement for first year (freshman) engineering students at the University of Pittsburgh Swanson School of Engineering. Thispaperis astudent, not a professional, paper. This paper is based on publicly available information and may not provide complete analyses of all relevant data. If this paper is used for any purpose other than these authors’ partial fulfillment of a writing requirement for first year (freshman) engineering students at the University of Pittsburgh Swanson School of Engineering, the user does so at his or her own risk.

PITTSBURGH CAN MAKE YOU FEEL THINGS

Katherine Dunkelberger ()

Katherine Dunkelberger

BIOENGINEERING, NEUROPROSTHETICS, AND ME

“You want to be a bioengineer? What is that?” my family and friends always seem to ask when I explain my intended major. I often respond with familiar bioengineering applications like prosthetics in order to illustrate my future career. Most people have a general understanding of prosthetics but are not aware of the exciting advancements happening in the field. Prosthetics, more specifically the bionic eye, was the first topic that piqued my interest in engineering. Though I have never met anyone in need of a bionic eye, I have known friends who would benefit from other neuroprosthetics. My mom helped a family friend suffering from multiple sclerosis who eventually lost control of his extremities. Sadly, he passed away a couple years ago. Although he always cracked jokes and maintained a positive attitude, I am sure he did not easily adjust to being wheelchair bound and unable to feed himself. While his physical functioning declined, he never lost his ability to think clearly and communicate.If he could have hadaneuroprosthetic arm, he could have been much more independent.

I continue to find advances in prosthetics, especially neuroprosthetics, captivating.I can picture myself working on clinical trials of neuroprosthetic devices because of my interest in them and my desire to help others through my career. Advances in prosthetics affect a large number of people, and advances in neuroprosthetics has applications to various prosthetics technologies. Cutting edge neuroprosthetic research is expanding the functionality of prosthetics and making progress toward lifelike devices.

AN OVERVIEW OF PROSTHETICS

Prosthetics is a field of biotechnology that creates and improves artificial body parts. Artificial limb technology is a well-known type of prosthetic, but cochlear implants and bionic eyes also classify as prosthetics. Prosthetics research impacts a significant portion of the population since the field has so many applications. According to the National Institute on Deafness and Other Communication Disorders, over 324,000 people have registered cochlear implants worldwide, and that number reflects only one specific prostheticdevice [1]. As technology continues to improve, prosthetic devices can function more like their corresponding body parts. Deeper research on the brain and nervous system and the ability to integrate technology into the human body contribute to this improvement. The human body is controlled by the nervous system, so the most lifelike prosthetics will also be controlled by the nervous system. As researchers endeavor to make realistic prosthetics, research in neuroprosthetics is growing at an impressive rate. Enhanced technology and governmental funding initiatives play integral roles in this expansion. The White House Frontiers Conference webpage describes how at the recent conference in Pittsburgh, President Obama announced new federal funding initiatives for neuroscience research [2].Investments in research and technology fuel the scientific feats necessary to make lifelike prosthetics for people who need them.

NEUROPROSTHETICS TECHNOLOGY

The article “Neuroprosthetics” by E. Leuthardt, J. Roland, and W. Rayin The Scientist defines a neuroprosthetic as “a device that supplants or supplements the input and/or output of the nervous system” [3]. In other words, this class of prosthetics either receives information from the nervous system or passes signals to the nervous system. Such technology requires sophisticated connections among computing systems to understand and use neurological signals. There are various methods for collecting nervous system information. “Neuroprosthetics” explains electroencephalography (EEG) which uses noninvasive techniques to read and record electric signals of the brain [3]. EEG allows scientists to understand some patterns of thought and utilize them to control devices. For example, EEG sensors could use the thoughts pattern of someone picturing a hand opening and closing to open and close a robotic hand [3]. While this type of brain-computer interface works for basic functions and requires relatively little set up, it has some limitations because the matter between the brain and the sensors complicates signal detection. EEG cannot record electrical neurological activity precisely or at high frequencies [3]. Moreover, this noninvasive approach records neurological signals, but it does not produce any. As medical, neurological, and computing knowledge and techniques progress, the application of technology to neuroprosthetics advances.

A more sophisticated technique for signal detection in neuroprostheticsimplants an electrode in the brain. This electrode can more accurately detect neurological activity over a larger range of frequencies. The Scientist’s article “Neuroprosthetics” explains that implantable electrodes can record signals down to the single-neuron level [3]. Since this newer technology can record more precise signals, these electrodes can better control prosthetic devices. To compare the prosthetic capabilities of noninvasive versus implantable signal dectectors, noninvasive methods could record a signal to open and close a prosthetic hand, whereas an implanted electrode could record a signal to move the fingers of a prosthetic hand.

The capabilities of prosthetic devices depends not only on the ability to collect brain activity, but also on the understanding of that activity. If the implantable electrodes record the activity of a single neuron, but scientists do not know what that neuron controls, then the information is useless. Fortunately, neurological research is mapping the brain and finding that certain patterns of activity correspond to actions. With implantable electrodes and brain mapping, researchers can see the brain activity of a person and make an educated guess at what that activity means. The last piece of the puzzle is applying that information to prosthetics. First, the prosthetic device would require programming to interpret the real brain activity of a patient and relate it to motions of the device. Then, the prosthetic would have to change the interpretations into executable actions of the device. Finally, the device would have to be engineered to move according to the appropriate actions. This processing and designing is the portion of neuroprosthetics that requires engineering. While engineers might be consulted in designing the implantable electrodes, neuroscientists and surgeons do most of the research on brain activity and signal recording. Engineers focus on applications of the recorded brain activity and on the design of the external technology.

The most recent advances in neuroprosthetics employ implanted electrodes. Their disadvantages include required surgery for implantation and potential loss of utility due to an immune response of the brain. The immune response called gliosis forms a layer around the implanted device and reduces the device’s ability to record brain activity per “Neuroprosthetics” [3]. Despite these challenges, implanted electrodes have incredible potential. In addition to relaying signalsof more sophisticated movements, these devices can generate electrical impulses, meaning they can potentially simulate the feelings of natural body parts. In the case of cochlear implants, the National Institute on Deafness and Other Communication Disorders explains that the device transfers sound data to the auditory nerve by means of a microphone and an electrode array [1]. The implanted electrodes for other neuroprostheses work on the same principle, but in a more sophisticated way. They transfer data directly into the brain rather than to a nerve, so defining the correct areas to receive certain sensations is much more challenging.

To complicate matters, different sensations contribute to the natural feeling of alimb. Touch, including the point of contact, pressure, and temperature of a stimulus and proprioception, or the feeling of where a body part is in space, are types of sensations that contribute to the usage of a limb. These senses function to provide information about the world and information about movements. Movement relies on the sensory feedback of previous movements, so incorporating sensations into prosthetics is essential to making the device realistic and practical. For example, the combination of sensations from a limballows someone to pick up a cupcake without squishing it.First, the muscles in the arm must adjust several joints to move the hand toward the cupcake. Proprioception facilitates this action by providing constant sensory feedback about the position of the limb. In the article “Neuroprosthetics: In search of the sixth sense” appearing in Nature, Allison Abbott describes a case of proprioception loss and the challenges of moving without that sense [4]. Individuals lacking proprioception have serious difficulty moving since they have to rely on other types of sensation to guide their movements. In addition to proprioception, the limb sends feedback about touch. The pressure felt in the hand when grasping the cupcake determines how much the hand needs to close and push on the cupcake. Without the sensory feedback, a person might apply too much force to the cupcake and crush it because there is no measure of the action aside from vision.

In order for implantable electrodes to recreate the sensation of an artificial limb, they must transmit all of this sensory data to the correct areas of the brain. Neuroscience has a long way to go to understand how and where the brain processes all sensory data, but current research is making strides using modern knowledge of the brain. Some of the most exciting research is happening in Pittsburgh.

PITTSBURGH BREAKTHROUGH

The Pittsburgh area recently earned recognition for its neuroprostheticsresearch presented at the White House Frontiers Conference. According to its webpage, the conference addressed“building U.S. capacity in science, technology, and innovation, and the new technologies, challenges, and goals that will continue to shape the 21st century and beyond” [2].The Defense Advanced Research Projects Agency published a news article about the conference, describing in the article “DARPA Helps Paralyzed Man Feel Again Using a Brain-Controlled Robotic Arm” how one of the innovations on display concerning neuroprostheticscaught the President’s attention. Based on the article “Intracorticalmicrostimulation of human somatosensory cortex” in The Scientist, researchers from the University of Pittsburgh and the University of Pittsburgh Medical Center (UPMC) presented their work on a neuroprosthetic robotic arm [5]. Nathan Copeland, a quadriplegic, operated the robotic arm via four microelectrode arrays implanted in his brain. An NBC article “Brain Chip Helps Paralyzed Man Feel His Fingers” by M. Fox reported Copeland’s introduction to the President. The two men shook hands and fist-bumped. Not only did Copeland control the robotic arm’s actions, he also experienced sensations accompanying the actions [6]. Researchers at the University of Pittsburgh and UPMC have been implementing and improving the sensory input of neuroprosthetics, and their work presented at the Frontiers conferenced discussed their progress.

The researchers’ results published in the article “Intracorticalmicrostimulation of human somatosensory cortex” claim to provide a basis for testing the sensory input experienced from implanted microelectrodes [7]. The study required implantation of microelectrodes into areas of the brain corresponding to touch sensation of the hand. The test subject, Copeland, experienced some spontaneous sensations after researchers implanted the microelectrodes, but these side effects subsided, and after two months the unsolicited sensations ceased. About five weeks after surgery when the spontaneous sensations began to subside, Copeland started experiencing the first successful stimulation by the microelectrodes. The researchers conducted testing over six months during which they activated the microelectrodes and recorded Copeland’s responses to several qualitative questions. Since generating natural sensations presents a serious challenge, researchers asked Copeland to classify how natural his sensations felt. He also reported the depth on which he felt the sensation, the level of pain, and the type of sensation. Most often, Copeland felt the sensations as if they originated both on the surface of the hand and within the hand. He did not report any pain associated with the stimulation of electrodes. The most common types of sensation reported were pressure and tingling. Researchers also investigated the intensity of sensation, the consistency of sensation,and the safety of stimulating the brain via microelectrodes. Furthermore, researchers checked the accuracy of sensations by testing how well Copeland could identify the intended location of the stimulus. While someone pressed on a finger of the robotic hand, Copeland guessed which finger they touched. He was correct over ninety percent of the time when the pointer or pinkie finger was touched and about seventy-five percent of the time when the middle or ring finger was touched. The microelectrodes did not extend to regions of the brain that correspond to the thumb [7].

The University of Pittsburgh and UPMC research provides exciting precedents for neuroprosthetics. Not only does the study produce a template for recreating sensations, but researchers also invented methods for testing qualities of stimulated sensations. Future research can build on the work done in Pittsburgh and continue to make prosthetics more realistic and useful.

SUMMARY OF NEUROPROSTHETICS AND ME

Research at the University of Pittsburgh and UPMC is the latest achievement in the growing field of neuroprosthetics. The research successfully provided sensory feedback from the prosthetic arm to the subject.The work incorporates implanted electrodes to control a robotic arm and receive sensory stimuli. Implanted electrodes exemplifyan advanced type of signal detector that can operate with prosthetic devices. Recent advances in neuroprosthetics are generating more natural prosthetic devices that can perform more functions. More lifelike prosthetics, especially those with sensory feedback, would improve the interactions with the world of those in need of prosthetics. Neuroprosthetics is just one of many bioengineering applications, andI would love to take part in neuroprosthetic research. Attending the University of Pittsburgh provides great opportunities inneuroprosthetic and other bioengineering research. These opportunities will prepare me for a future career involved with clinical trials to develop technology that helps people.

SOURCES

[1] National Institute on Deafness and Other Communication Disorders. “Cochlear Implants.” NIDCD Fact Sheet: Hearing and Balance. 2.2016. Accessed 10.27.2016.

[2]”The Conference.” The White House Frontiers Conference. 10.2016. Accessed 10.29.2016

[3]E. C. Leuthardt, J. L. Roland, W. Z. Ray.“Neuroprosthetics.”The Scientist.11.1.2014. Accessed 10.27.2016.

[4] A. Abbott. “Neuroprosthetics: In search of the sixth sense.” Nature. 7.13.2006. Accessed 10.31.2016.

[5] Defense Advanced Research Projects Agency. “DARPA Helps Paralyzed Man Feel Again Using a Brain-Controlled Robotic Arm.” DARPA News and Events. 10.13.2016. Accessed 10.27.2016

[6] M. Fox. “Brain Chip Helps Paralyzed Man Feel His Fingers.” NBC News. 10.13.2016. Accessed 10.27.2016.

[7] S. N. Flesher, J. L. Collinger, S. T. Foldes, J. M. Weiss, J. E. Downey, E. C. Tyler-Kabara, S. J. Bensmaia, A. B. Schwartz, M. L. Boninger, R. A. Gaunt. “Intracorticalmicrostimulation of human somatosensory cortex.” The Scientist. 10.19.2016. Accessed 10.27.2016.

ACKNOWLEDGEMENTS

Thank you to President Obama for acknowledging the awesome innovation happening in Pittsburgh and indirectly providing some material for this essay. Thank you to my writing instructor, Professor Zelesnick, for answering my mass of questions. Thank you to my Dad for showing me articles about neuroprosthetics years ago and getting me interested in the field. Thank you to Tony Gravante for being a good influence on me and correcting my perspective. Thank you to my friends in Forbes for encouragement.