Introduction to Neural Prosthesis Sung June Kim Neural Prosthetic Engineering 1 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. Neural Prosthetic Engineering 2 Successful Areas of Neural Prosthesis • (Bionic Ear) • Hearing: Cochlear Implant • Vision: Retinal Implant • Parkinson’s Disease: DBS (Deep Brain Stimulation) Neural Prosthetic Engineering 3 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. Neural Prosthetic Engineering 4 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. http://www.cochlearamericas.com/ Neural Prosthetic Engineering 5 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 Neural Prosthetic Engineering 6 Speech Processor, An example of External Unit 7 www. bionicear.com, www.medel.com, www.cochlear.com Neural Prosthetic Engineering 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 Neural Prosthetic Engineering 8 Example of the Internal Unit 10 mm Neural Prosthetic Engineering 9 Nurobiosys Corp., Korea 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. External Unit Internal Unit Neural Prosthetic Engineering 10 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. External Unit Internal Unit Neural Prosthetic Engineering 11 System example: Cochlear Implant ③ Data & Power Transmission Microphone Internal Coil External ④ Signal Coil Demodulation Implantable Current Stimulator ① Sound Signal ⑥ Auditory Cortex ② RF Modulation ⑤ Stimulation Inserted Pulse train Electrode array Wearable Speech Processor Neural Prosthetic Engineering 12 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 Neural Prosthetic Engineering 13 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. Neural Prosthetic Engineering 14 Neural prosthetic Milestones 1961: 1st motor 1952: Hodgkin- 1977: Bone-anchored prosthesis for foot hearing aid made Huxley theory of drop in hemiplegics action potential available in Europe 1957: 1st cochlear implant developed 1973-74: organized clinical trials of the 1979: 1st 1934: Electronic 1958: Internal 1st wearable cochlear auditory hearing aid developed pacemaker implant begin brainstem developed implant 1930 1940 1950 1960 1970 1971: 1945: Invention 1956 Nobel Prize 1961: Silicon Microprocessor of transistor of Physics awarded chips first appear invented (Intel, to Shockley, (TI, J. Kilby) 4004) Bardeen and Brattain 1963: CMOS 1977: VLSI invented developed(Modular 1959: MOSFET (Fairchild, design by Mead invented (BL, Wanlass) and Conway) D.Khang) Engineering/Computer Milestones 15 Finn, Warren E., and Peter G. LoPresti, eds. Handbook of neuroprosthetic methods. CRC Press, 2002. Neural prosthetic Milestones 1980: 1st successful 1995: 1997: 2000: 1986-95: FES allows FDA approval 1-channel cochlear paraplegics to stand - Human trials of visual - FDA authorizes implant in a child cortex prosthesis of DBS on Optobionics to begin - German group begin thalamus for human trials of Subretinal implant Parkinson’s Artificial Silicon 1981: Peripheral nerve Disease Retina (ASR) bridge implanted into st 1996: Optic nerve - FDA approval of 1 spinal cord of rat 1988: MIT-Harvard, prosthesis middle-ear implant Johns Hopkins begin development - FAD approval of research on begins in Belgium auditory brainstem epiretinal implant implant 1980 1985 1990 1995 2000 1981: IBM PC, STM invented 2000: Deep Brain Stimulation (ACTIVA) develped to treat 1985: MS Windows Parkinson’s disease developed 1980: silicon 1989: Intel 486 1998: Google microelectrode for processor extracellular recording begun Engineering/Computer Milestones 16 Finn, Warren E., and Peter G. LoPresti, eds. Handbook of neuroprosthetic methods. CRC Press, 2002. Neural prosthetic Milestones 2005-2009: 2004: 1500 channel subretinal Human- photodiode array by implanted BCI German group 2005: Optogenetic 2013: FDA approval of system for 2007: clinical trials of Secondsight Argus II 2002-2004: 16-channel mammalian 60-channel Argus II epiretinal prosthesis retinal prosthesis Argus I neuron begin developed 2000 2005 2010 2015 2008: 2010: 2012: 2014: 2003: completion iPhone 3G iPhone 4 iPhone 5 iPhone 6 of the Human Genome Project 2001: 2006: 1st Tesla all- st 1 dual-core 2004: electric vehicle processor (IBM) Facebook launched Engineering/Computer Milestones 17 Neural Prosthetic Engineering • Biomedical Engineering. • A Biomedical engineer is one who challenges many problem in the modern heath care system. • Neural Engineering • Artificial Organs (Devices for replacement or augmentation of bodily functions) • Can join professional societies such as IEEE EMBS (Engineering in Medicine and Biology Society). They hold annual meeting called EMBC (Engineering in Medicine and Biology Conference). • BMES (Biomedical Engineering Society) is another major biomedical engineering society. 18 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) 19 http://www.ieee.org/embs 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) • International Neuromodulation Society(INS) World Congress • Society for Neuroscience(SFN) Conference • World Society for Stereotactic Functional Neurosurgery(WSSFN) • International Federation for Medical & Biological Engineering(IFMBE) 20 Journals we can publish our research in • Includes, but not limited to, • Biosensors and Bioelectronics • Journal of Neural Engineering • Investigative Ophthalmology & Visual Science • Journal of Neuroscience Methods • Clinical & Experimental • Medical & Biological Engineering & Otorhinolaryngol Computing • Optics Letters • Biomedical Instrumentation and Technology • Biotechnology and Bioengineering • Journal of Clinical Engineering • Neuromodulation • Computer Methods and Programs • Nanotechnolgy in Biomedicine • Optics Communications • Neural Computation • NeuroImage • Science • Invest Ophthalmol Vision Science • Nature • Tissue Engineering • Small • Bioelectromagnetics • Optics Express • Sensors • Otology and Neurotology • Journal of Materials Science: • Journal of Neuromodulation Materials in Medicine • Sensors and Materials • Journal of Biomedicine and Biotechnology • Sensors & Actuators • Biochimica et Biophysica Acta • Computational and Mathematical Methods in Medicine • Medical Engineering & Physics • ACS Nano • And more. 21 Cochlea’s Operating Principle Cochlear's operating principles Cochlear implant electrically stimulates neural