Introduction to Neural Prosthesis

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Neural Prosthetic Engineering

Introduction to Neural Prosthesis

Sung June Kim

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Neural Prosthesis

• A device that connects directly with the nervous system to replace or supplement sensory or motor function.

• A device that improves the quality of life of a neurologically impaired individual so much

that he/she is willing to put up with the

surgery, gadgetry, etc.

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Successful Areas of Neural Prosthesis

• (Bionic Ear)

• Hearing: Cochlear Implant

• Vision: Retinal Implant

• Parkinson’s Disease: DBS (Deep Brain Stimulation)

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Why these three?

• Success in Cochlear Implant

• The other two were inspired by its (the CI’s) success.

• The Cochlear and Retinal implants are sensory prosthetics, using electrical stimulation of

neurons.

• The DBS deals with motion disability yet uses CI like neuronal stimulation.

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Why was CI so successful?

• Spatially isolated space was available for the electrode array. The electrode array was still electrically connected to the target neurons.

• Timely development of the transistor based microelectronics technologies that made the electronics small (wearable, implantable) but powerful.

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http://www.cochlearamericas.com/

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What are needed in NP? (1)

• External unit is needed if there is a signal to process.

• Speech is the signal to process in Cochlear Implant

• Image is the signal to process in Retinal Implant

• There is no external signal to process in DBS.

External Unit

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Speech Processor, An example of External Unit

www. bionicear.com, www.medel.com, www.cochlear.com 7

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What are needed in NP? (2)

• Internal Unit (Implantable Unit)

• This unit generates electrical signals, and apply them to the array of electrodes that stimulate target neurons.

External Unit Internal Unit

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Example of the Internal Unit

Nurobiosys Corp., Korea⁹

10 mm

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What are needed in NP? (3)

• Communication (Connection) between the two.

• If the connection is wired, it is called

“percutaneous connection”,

• Percutaneous connection is simplest, best with signal to noise ratio, but there is risk for

infection.

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What are needed in NP? (4)

• Thus modern NP uses wireless communication (telemetry).

• The telemetry requires extra circuit to transmit and receive signals from the external unit to the internal one.

• There are forward telemetry and reverse telemetry.

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System example: Cochlear Implant

Microphone External Coil

Internal Coil

Implantable Current Stimulator

Inserted

Electrode array

① Sound Signal

② RF Modulation

③Data & Power Transmission

⑤ Stimulation Pulse train

④ Signal Demodulation

⑥Auditory Cortex

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Problems addressed

• Cell loss is the common problem.

• Cells that act as transducers (sensors) for hearing and vision

– Hair cells in cochlea in hearing impairment

– Photoreceptor cells in retina for vision impairment

• Cells that are essential in controlled movement:

– Substantia Nigra cells in Parkinson’s disease

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Possible solutions

• Stem cells: IPSC (Induced Pluripotent Stem Cells) are the typical approach

• However, these are not proven safe for clinical applications yet.

• Currently Neural Prosthesis is the only working solution: An array of electrodes are inserted to electrically stimulate surviving neighbor neuron cells to substitute or replace the lost functions.

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Neural prosthetic Milestones

1930 1940 1950 1960 1970

1934: Electronic hearing aid developed

1945: Invention

of transistor 1956 Nobel Prize of Physics awarded to Shockley,

Bardeen and Brattain 1952: Hodgkin- Huxley theory of action potential

1957: 1^st cochlear implant developed

1958: Internal pacemaker developed

1959: MOSFET invented (BL, D.Khang)

1961: 1^st motor prosthesis for foot drop in hemiplegics

1961: Silicon chips first appear (TI, J. Kilby)

1963: CMOS invented (Fairchild, Wanlass)

1977: Bone-anchored hearing aid made available in Europe

1977: VLSI

developed(Modular design by Mead and Conway) 1973-74: organized

clinical trials of the 1^st wearable cochlear implant begin

1971:

Microprocessor invented (Intel, 4004)

1979: 1^st auditory brainstem implant

Engineering/Computer Milestones

Finn, Warren E., and Peter G. LoPresti, eds.Handbook of neuroprosthetic methods. CRC Press, 2002. 15

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Neural prosthetic Milestones

1980 1985 1990 1995 2000

1980: 1^st successful 1-channel cochlear implant in a child

1981: IBM PC, STM invented

1986-95: FES allows paraplegics to stand

1981: Peripheral nerve bridge implanted into spinal cord of rat

1995:

- Human trials of visual cortex prosthesis

- German group begin Subretinal implant

2000:

- FDA authorizes Optobionics to begin human trials of Artificial Silicon Retina (ASR)

- FDA approval of 1^st middle-ear implant - FAD approval of

auditory brainstem implant

1996: Optic nerve prosthesis

development begins in Belgium

1985: MS Windows developed

1988: MIT-Harvard, Johns Hopkins begin research on

epiretinal implant

1997:

FDA approval of DBS on thalamus for Parkinson’s Disease

2000: Deep Brain Stimulation (ACTIVA) develped to treat Parkinson’s disease

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Neural prosthetic Milestones

2000 2005 2010 2015

2008:

iPhone 3G

Engineering/Computer Milestones

2010:

iPhone 4 2012:

iPhone 5 2014:

iPhone 6 2013: FDA approval of Secondsight Argus II epiretinal prosthesis 2002-2004: 16-channel

retinal prosthesis Argus I developed

2007: clinical trials of 60-channel Argus II begin

2005-2009:

1500 channel subretinal photodiode array by German group

2003: completion of the Human Genome Project

2005:

Optogenetic system for mammalian neuron

2001:

1^st dual-core processor (IBM)

2006: 1^st Tesla all- electric vehicle 2004:

Human- implanted BCI

2004:

Facebook launched

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Our envinronment

• We are certainly a Biomedical Engineer

• Biomedical engineer is who challenges many problem in the modern heath care system.

• To be more specific, we could be called a Neural Engineer.

• Some people might say we study Artificial Organs (Devices for replacement or augmentation of bodily functions)

• We can join professor societies such as IEEE EMBS

(Engineering in Medicine and Biology Society). They hold

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IEEE EMBS

• IEEE Engineering in Medicine and Biology society

• The IEEE is the largest international professional organization in the world and accommodates 37 different societies and councils under its umbrella structure.

• The EMBS represents the foremost international organization serving the need of more than 8000 biomedical engineering members around the world.

• publications:

• Transaction on Biomedical Engineering(TBME: a monthly journal)

• Transactions on Biomedical Circuits and Systems

• Transaction on Rehabilitation Engineering

• Transaction of Information Technology in Biomedicine(two quarterly journals))

• IEEE Engineering in Medicine and Biology magazine(a bimonthly magazine)

http://www.ieee.org/embs 19

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Conferences and Meetings we can travel to

• Institute of Electrical and Electronic Engineers(IEEE) Engineering in Medicine and Biology Society(EMBS) Conference

• IEEE EMBS Neural Engineering Conference

• Biomedical Engineering Society(BMES) Meeting

• Neural Interfaces Conference

• Biomedical Circuits and Systems(BioCAS) Conference

• Conference on Implantable Auditory Prostheses(CIAP)

• European Symposium on Paediatric Cochlear Implantation(ESPCI)

• Asia Pacific Symposium on Cochlear Implant and Related Sciences(APSCI)

• American Cochlear Implant Alliance CI Symposium

• The Eye and The Chip Meeting

• Annual Meetings of Association for Research in Vision and Ophthalmology (ARVO)

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Journals we can publish our research in

• Includes, but not limited to,

• Journal of Neural Engineering

• Journal of Neuroscience Methods

• Medical & Biological Engineering &

Computing

• Biomedical Instrumentation and Technology

• Journal of Clinical Engineering

• Computer Methods and Programs in Biomedicine

• Neural Computation

• Science

• Nature

• Small

• Optics Express

• Otology and Neurotology

• Journal of Neuromodulation

• Sensors and Materials

• Sensors & Actuators

• Computational and Mathematical Methods in Medicine

• ACS Nano 21

• Biosensors and Bioelectronics

• Investigative Ophthalmology &

Visual Science

• Clinical & Experimental Otorhinolaryngol

• Optics Letters

• Biotechnology and Bioengineering

• Neuromodulation

• Nanotechnolgy

• Optics Communications

• NeuroImage

• Invest Ophthalmol Vision Science

• Tissue Engineering

• Bioelectromagnetics

• Sensors

• Journal of Materials Science:

Materials in Medicine

• Journal of Biomedicine and Biotechnology

• Biochimica et Biophysica Acta

• Medical Engineering & Physics

• And more.

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Introduction to Neural Prosthesis