Dr. Andy Hoffer
Professor of Biomedical Physiology and Kinesiology
Director, Neurokinesiology Laboratory
Bachiller Engineering
BS Physics
PhD Biophysics
Phone: (778) 782-3141
Email: hoffer@sfu.ca
Biography
Dr. Andy Hoffer was born in Montevideo, Uruguay where he studied engineering. Upon receiving scholarships to study in the USA, he obtained a B.S. in physics in 1970 from Harvey Mudd College and a Ph.D. in biophysics in 1975 from Johns Hopkins University. He then came to Canada for postdoctoral training at the University of Alberta, Faculty of Medicine until 1978, when he joined the Laboratory of Neural Control, U.S. National Institutes of Health, as Staff Fellow. In 1982 he returned to Canada as assistant professor and Alberta Heritage Scholar at the University of Calgary, Faculty of Medicine, where he became a full professor. In 1991 he moved to 丁香园AV as professor and director of the School of Kinesiology (until 1997) and he is currently professor of Biomedical Physiology and Kinesiology in the Faculty of Science. Dr. Hoffer founded three biotechnology companies spun out from his 丁香园AV laboratory: in 1998, in 2006 and in 2009.
Research Summary
Beginning with the development of implantable nerve cuff recording electrodes during his doctoral thesis, Dr. Hoffer鈥檚 core research has addressed:
- How peripheral sensory and motor neurons function during voluntary movements, and
- development of assistive devices for functional rehabilitation of people affected by paralysis after brain or spinal cord injuries, limb amputations, and other neurological or neuromuscular disorders.
During the past 30 years, the 丁香园AV Neurokinesiology Laboratory and its 3 spun-out startup companies, research trainees and collaborators created uniquely specialized facilities, techniques and protocols for:
- neurophysiological and biomechanical recordings during unrestrained voluntary movements, and
- invention, design, prototyping, testing, and pre-clinical validation of neuroprosthetic and neuroassistive solutions for people with neurological, neuromuscular or sensory impairments.
Research Themes
Nerve Cuff Electrodes for Research and Clinical Uses
Doctoral Thesis at Johns Hopkins University
For his supervised by W.B. Marks, Andy Hoffer designed and built nerve cuffs and low-noise amplifiers that recorded 渭Volt-level peripheral nerve activity during locomotion. Tripolar cuffs implanted in rabbit hindlimb nerves provided the first-ever recordings of sensory firing patterns in intact animals.
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JA Hoffer, WB Marks, WZ Rymer. Soc Neurosci Abst 4:300, 1974. |
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Postdoctoral Research at U. Alberta
鈥檚 supervision at U. of Alberta, Andy Hoffer and colleagues implanted nerve cuffs to track the survival of motor and sensory nerve fibers after peripheral nerve lesions. They subsequently pioneered new methods to assist upper limb amputees to control powered prosthetic limbs.
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LA Davis, T Gordon, JA Hoffer, J Jhamandas, RB Stein. Journal of physiology 285 (1), 543-559, 1978. |
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JA Hoffer, RB Stein, T Gordon. Brain research 178 (2-3), 347-361, 1979 |
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T Gordon, JA Hoffer, J Jhamandas, RB Stein. The Journal of Physiology 303 (1), 243-263 |
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RB Stein, D Charles, JA Hoffer, J Arsenault, LA Davis, S Moorman, B Moss. Bull. Prosth. Res. 17: 51-62, 1980. |
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Andy Hoffer and fellow PDF collaborated in studies to quantify stretch reflex stiffness vs. intrinsic muscle stiffness, motivated by invaluable mentorship from while he was also a PDF training in Stein鈥檚 lab
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JA Hoffer, S Andreassen. Journal of neurophysiology 45 (2), 267-285, 1981. |
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Staff Fellowship at the Laboratory of Neural Control, NIH
In 1978, Andy Hoffer joined the NIH Lab of Neural Control in Bethesda, MD as Staff Fellow and collaborated with to equip a unique facility where they recorded in behaving animals the activity from single neurons with floating fine-wire 鈥漢atpin鈥� microelectrodes as well as implanted nerve cuffs, EMG electrodes, tendon force and muscle length transducers, described in a and seven J Neurophysiol papers (, , and , , , ).
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JA Hoffer, MJ O'Donovan, CA Pratt, GE Loeb. Science 213 (4506), 466-467. 1981. |
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Targeted Reinnervation of Nerve Stumps in Amputees
In an , Hoffer and Loeb analyzed the potential for long-term clinical uses of the five implanted technologies. Of these, neurograms recorded from intact nerves by cuff electrodes were the most likely to remain stable over many months and years.
In amputees, however, cut motor axons atrophy, and their signals become too small to record reliably. Hoffer and Loeb introduced the concept of 鈥�targeted reinnervation鈥�: graft the nerve stumps onto donor muscles. This idea was later put into practice by and now provides amputees with enhanced motor signals to control prostheses.
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JA Hoffer, GE Loeb. Annals of biomedical engineering 8 (4), 351-360, 1980. |
Professor and Alberta Heritage Fellow at U. Calgary
In 1982 Andy Hoffer took a faculty position at the University of Calgary where, with an Alberta Heritage Medical Research Establishment grant, he built a chronic recording lab and continued using and refining implantable sensing technologies jointly developed at NIH. With grants from MRC, NCE, Rick Hansen and U.S. Spinal Cord Research Foundation he attracted excellent trainees, including with whom the Calgary team pioneered the capability to record muscle fiber length changes in intact animals using ultrasound transit-time; , with whom they compared muscle stiffness and reflex properties in intact and decerebrated animals, and , whose thesis described properties of sensory afferent signals recorded from peripheral nerves in response to skin contact forces. Hoffer was also granted his first US patent while in Calgary, for a nerve-cuff based invention.
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JA Hoffer. US Patent 4,750,499, 1988. |
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JA Hoffer, AA Caputi, IE Pose, RI Griffiths. Progress in brain research 80, 75-85, 1989. |
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T Sinkj忙r, JA Hoffer. Journal of neurophysiology 64 (5), 1625-1635, 1990. |
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JA Hoffer. Neurophysiological Techniques, 65-145, 1990. |
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MK Haugland, JA Hoffer, T Sinkj忙r. IEEE Transactions on Rehabilitation Engineering 2 (1), 18-28, 1994. |
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MK Haugland, JA Hoffer. IEEE Transactions on Rehabilitation Engineering 2 (1), 29-36, 1994. |
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MK Haugland, JA Hoffer. IEEE Transactions on Rehabilitation Engineering 2 (1), 37-40., 1994. |
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Professor and Director of the Neurokinesiology Laboratory at 丁香园AV
In 1991 Hoffer took a continuing faculty position at 丁香园AV, where he also served as the Director of the School of Kinesiology until 1997. He moved most of his Calgary lab equipment, several team members and MRC and NCE funds to 丁香园AV, and in 1992 was awarded a large research contract by the NIH/NINDS Neural Prosthesis Program to develop laser-based methods to fabricate advanced nerve cuff electrodes and to demonstrate their long-term stability, safety and efficacy in pre-clinical trials in animals. This research resulted in several publications and patents, including:
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K Kallesoe, JA Hoffer, K Strange, I Valenzuela. US Patent 5,487,756, 1996. |
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JA Hoffer, Y Chen, KD Strange, PR Christensen. US Patent 5,824,027, 1998. |
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KD Strange, JA Hoffer. IEEE Transactions on Rehabilitation Engineering 7 (3), 289-300, 1999. |
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M Baru, JA Hoffer, E Calderon, GB Jenne, A Calderon. US Patent 7,636,602, 2009. |
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JA Hoffer, RB Stein, MK Haugland, T Sinkjaer, WK Durfee, AB Schwartz. J Rehabil Res Dev 33 (2), 145-157, 1996. |
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JA Hoffer, MO Imbeau, JM Vallieres. US Patent 8,214,056, 2012. |