An Assortment of Electrical and Computer Engineering Topics

An Assortment of Electrical and Computer Engineering Topics in Biomedical Engineering Edward (Ted) A. Clancy Department of Electrical and Computer Engineering Department of Biomedical Engineering Worcester Polytechnic Institute, USA Copyright Edward A. Clancy, 2011. Some rights reserved. Content in this presentation is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3. 0 License. This license is more fully described at: http: //creativecommons. org/licenses/by-nc-sa/3. 0/. Many of the videos shown during this presentation are posted at: http: //ece. wpi. edu/~ted/teach. htm EAC 12– 100 c

Electrophysiologic Monitoring Electrical Activity in the Human Body Biosignal Electrocardiogram (ECG or EKG) Electrical activity of the … … heart (www. aic. cuhk. edu. hk) Example Uses - Patient monitoring - Diagnose “heart attack, ” arrhythmia Electroencephalogram … brain (EEG) - Anesthesia monitoring - Seizure analysis Electromyogram (EMG) - Prosthesis control - Motion control, ergonomics studies - Clinical EMG exam - Clinical gait analysis - Sports, exercise (www. cogneuro. ox. ac. uk) … muscles (people. uleth. ca ) EAC 08– 201

Electrophysiologic Monitoring Simple ECG Lead System From: nurse. CE. com EAC 08– 202

Electrophysiologic Monitoring ECG—Electrocardiogram • Electrical activity of the heart EAC 08– 203

Electrophysiologic Monitoring ECG Arrhythmias • Abnormal rates (fast, slow, varied, not varied!) • Abnormal shapes www. physionet. org EAC 08– 204

Electrophysiologic Monitoring Measuring Respiration from ECG • Respiration modulates the ECG! Moody et al. , Computers in Cardiology 12: 113– 116, 1985. • Many more direct measures – Chest band, capnograph (for CO 2), chest impedance EAC 08– 205 a

Electrophysiologic Monitoring “Alternation is Everything” • Alternans – Every other beat alternation in shape – Associated with sudden cardiac death Healthy Alternans EAC 08– 206 Clancy M. S. , 1987.

Electrophysiologic Monitoring Ambulatory Monitors Monitor abnormal rates, shapes, etc. ECG, Blood pressure, Sa. O 2, respiration, … www. nihonkohden. com EAC 08– 207

Electrophysiologic Monitoring EEG—Electroencephalogram • Electrical activity of the brain www. abc. net. au EAC 08– 208

Electrophysiologic Monitoring Some Characteristic EEG medical-dictionary. thefreedictionary. com EAC 08– 209

Electrophysiologic Monitoring Epilepsy • Abnormal brain discharges – Altered consciousness, abnormal movement/ sensation, changed behavior – Seizures • EEG: Spike discharges epilepsygroup. com EAC 08– 210

Electrophysiologic Monitoring Motor Unit Decomposition Motor unit potential with reinnervation Decomposition Shows: • Firing times, firing shapes • Scientific, physiologic, clinical information Partial Denervation: EMG • High amplitude, long duration, polyphasic, late potentials Sweep speed = 10 ms/div; Sensitivity = 1. 0 m. V/div (http: //www. neuro. wustl. edu/neuromuscular/pathol/diagrams/linkedpot. htm) EAC 08– 211

Neuro-Prostheses • “Emerging” field; Sub-set of neural engineering • Any prosthesis related to nerves, e. g. – Brain – Sensory nerves – Motor nerves • Early successes: – Cochlear implants – Deep brain stimulation EAC 09– 002

Neuro-Prostheses Cochlear Implants Restore Hearing www. hearingloss-wa. org www. childrensspecialists. com EAC 09– 003

Neuro-Prostheses Deep Brain Stimulation • Reduce tremor in Parkinson’s • Suppress depression ‒ experimental www. henryfordhealth. org EAC 09– 004

Neuro-Prostheses Other Neuroprosthesis Research • Artificial vision – Retinal and cortical prostheses • • Cortical and deep brain implants Motor neuroprostheses Functional electrical stimulation Artificial sensation – Motor position, velocity, force; temperature EAC 09– 005

Limb Prostheses Goal: 1970’s “Six Million Dollar Man” See file: “sixmilliondollarman. flv” Video available on You. Tube. com EAC 09– 006

Limb Prostheses Body-Powered Upper Limbs • Basic concepts date to civil War medicine See file: “Prosthetic Arm Tip #2: Tying a Shoe. flv” Video available on You. Tube. com EAC 09– 007

Limb Prostheses EMGamp: Myoelectric Control of Prosthesis • Use remnant muscle EMG to command electric hand, wrist, elbow – Some lower limb prosthetics research Boston Elbow — Liberating Technologies, Holliston, MA EAC 09– 008

Limb Prostheses EMG Amplitude (EMGamp) Estimation • EMG Amplitude (EMGamp): “Intensity” of recorded EMG – “Time-varying standard deviation of EMG signal” • Original estimator: Inman et al. [1956] – Analog full-wave rectify and RC low pass filter EMGamp – Varies with force Electrode-Amplifier (From Liberating Technologies) EMG amplitude 0– 10 m. V (~1. 5 m. V rms) Surface EMG frequency bandlimited at 2000 Hz EAC 09– 009

Limb Prostheses Nerve Re-Innervation for Myocontrol • Kuiken nerve reinnervation surgery • Nerves from severed limb re-connected to pectoralis muscle regions • Several myocontrol sites created • Substantial improvement RIC Arm; www. popsci. com EAC 09– 010

Limb Prostheses Myoelectric Control Example (Movie) (Click on black edge): “bionic_arm_BB. wmv” Jesse Sullivan video (Available on You. Tube. com) EAC 09– 011

Limb Prostheses Recent Limb Prosthetics Efforts • Major current effort by U. S. military to improve prosthetic limbs – Improved myoelectric controls – Embedded neural-/myo-sensors for control/sensation – Directly connect limb to bone 1) See file: “CNN Tech 08 -05 -16 Hand To Amputees. flv” Both videos from You. Tube. com 2) See file: “DARPA's Bionic Arm. flv” EAC 09– 012

Limb Prostheses EMG Testing Simulator • 2010 WPI senior project (Jung, Meklenburg, Patrick) • Emulates EMG signal. Used as testing input to new (Click on photo) prosthesis, prosthesis under repair. EAC 10– 012 a

Some Lower-Limb Prosthesis Research • Hugh Herr, MIT • Variable damper knee prosthesis – See file “knee. ram” EAC 09– 013

Rehab: Herr Ankle-Foot Orthosis • Compliant ankle: See file: “AAFO. ram” EAC 09– 015

Sroke/TBI Rehabilitation Rehab: MIT-MANUS • Compliant wrist, elbow rehab robot See file: “CNN 14 May 2006. mpg” From MIT Newman Lab (Click just below in white) • Developing ankle robot EAC 10– 016 a

Steve Bitar Heartbeat Monitor Lab • Phototransistor monitors finger pulse pressure (photoplethysmogram—PPG) • Simple lab used in WPI ECE, etc. • See: http: //ece. wpi. edu/~sjbitar/Project_Pulse_Kit/ EAC 10– 100

Bitar Heartbeat Monitor Lab (2) • If oscilloscope is used, only require: – R 1, R 2, LED 1, Q 1, 9 V battery EAC 10– 101

Bitar Heartbeat Monitor Lab (3) • Hold finger over LED, monitor collector of Q 1 DC coupled, low gain AC coupled, high gain EAC 10– 102

Active Research in Limb Prostheses • Walter Reed Hospital, Military Amputee Research Program (MARP) • [http: //www. tatrc. org/prosthetics] [http: //www. tatrc. org/portfolios. html#advanced_prosthetics] “Advanced Prosthetics and Human Performance” Portfolio; Telemedicine and Advanced Technology Research Center (TATRC) , U. S. Army Medical Research and Materiel Command • [http: //www. ninds. nih. gov/research/npp/resources/] National Institutes of Health (NIH), National Institute of Neurological Disorders and Stroke (NINDS), “Neural Interfaces Resources & Contracts” web page • [http: //www. darpa. mil/dso/thrusts/bio/restbio_tech/revprost/index. htm] “Revolutionizing Prosthetics” Program, Defense Advanced Research Projects Agency (DARPA) • [http: //www. jhuapl. edu/newscenter/pressreleases/2007/070426. asp] April 2007 update on the work of John’s Hopkins researchers on the DARPA “Revolutionizing Prosthetics” project EAC 09– 017