Andy Hoffer

Research Interests

I dedicated the first part of my research career to studying the roles and activity patterns of peripheral motor and sensory neurons involved in control of normal movements, for which I needed to develop novel implantable sensing methods and devices. In order to record and analyze the activity patterns of peripheral neurons during movements, I developed the first nerve cuff recording electrodes as well as other types of permanently implanted sensors and transducers. Subsequently, clinical applications of these implantable technologies became realistic research targets as we introduced advanced nerve cuff electrode designs and demonstrated their safety and efficacy in long-term implant experiments, funded to a large extent by the NIH/NINDS Neural Prosthesis Program.

In 1997 I founded Neurostream Technologies, a SFU spin-off company based in Port Coquitlam, BC and served continuously as the chief scientific officer until 2004. We raised 3 rounds of private investment and assembled an experienced technical, clinical-regulatory and management team. Between 2001 and 2004 we developed Neurostep^TM, the first fully implanted prototype assistive device for walking in hemiplegics. The Neurostep includes two implanted cuff electrodes that sense nerve signals from nerves and activate the paralyzed muscles that lift the foot in the affected leg. The cuffs are connected to a cell phone-sized control unit that includes patented chip-based, low-noise nerve signal amplifiers. In 2003-4 Neurostream tested the first Neurostep prototype in a pilot trial in a stroke subject with foot drop. In July, 2004 Neurostream was purchased by Victhom Human Bionics, a Quebec-based company (www.victhom.com). Victhom continued to develop the Neurostep system, carried out multi-centre clinical trials in Vancouver, Quebec and India and in Feb. 2009 obtained the CE Mark, allowing sales in Europe. Since June 2009, Neurostream Technologies is jointly owned by Victhom and Otto Bock (Germany).  I continue to assist Neurostream as a neurotechnology consultant and a member of the Scientific Advisory Board.

In 2005-2007 I started two new collaborative research projects at SFU, one with Dr. Faisal Beg on imaging of human peripheral nerves, funded by the Rick Hansen Man in Motion Foundation, another with Dr. Max Donelan on development of a biomechanical energy harvester for which we jointly obtained NSERC I2I funding, filed patents, published a paper in Science and co-founded another SFU spin-off company, Bionic Power, Inc.

In January, 2007 I started a new research program that is currently the central theme in the Neurokinesiology Lab in order to develop a minimally invasive transvascular nerve stimulation approach for "pacing" the diaphragm. This research is funded since 2008 by an NSERC I2I grant.  In May 2009 I founded a third SFU spin-off company, Lungpacer Medical, Inc., to develop commercial products based on this new approach to assist people who have respiratory insufficiency of neurological origin and depend on mechanical ventilation for survival.

The SFU Neurokinesiology Laboratory provides a specialized facility for interlinked neurokinesiological and neurophysiological research on the neural control of voluntary movement, as well as for development of neuroprosthetic methods to treat or assist people who have motor dysfunctions of neurological origin.

Patents and Licenses

1. Closed-loop, Implanted-sensor, Functional Electrical Stimulation System for Partial Restoration of Motor Functions. United States Patent 4,750,499, awarded to J.A. Hoffer on June 14, 1988.

2. Implantable Cuff having Improved Closure. United States Patent 5,487,756, awarded to K. Kallese, J.A. Hoffer, K. Strange and I. Valenzuela, January 30, 1996.

3. Nerve Cuff having One or More Isolated Chambers. United States Patent 5,824,027, awarded to J.A. Hoffer, Y. Chen, K. Strange and P. Christensen, October 20, 1998.

4. Implantable Cuff having Improved Closure, Canada Patent 2,139,097 awarded to K. Kallese, J.A. Hoffer, K. Strange and I. Valenzuela, Aug. 19, 2003.

5. Nerve Cuff having One or More Isolated Chambers. European Patent No. 1,001,827 awarded to J.A. Hoffer, Y. Chen, K. Strange and P. Christensen, 14 January 2004.

6. Electrical stimulation method for treating phantom limb pain and/or for providing sensory feedback arising from a prosthetic limb. J.A. Hoffer. International P.C.T. Patent filed July 5, 2000.

7. Implantable nerve signal sensing and stimulation device and method for treating foot drop and other neurological disorders. M. Baru, J.A. Hoffer, E. Calderon, G. Jenne and A. Calderon. International Patent application PCT/IB2004/001023 filed April 2, 2004, published 14 October 2004.

8. Implantable nerve signal sensing and stimulation device and method for treating foot drop and other neurological disorders. M. Baru, J.A. Hoffer, E. Calderon, G. Jenne and A. Calderon. United States Patent Application number 20050010265 filed April 2, 2004, published 13 January 2005.

9. Implantable modular, multi-channel connector system for nerve signal sensing and electrical stimulation applications. J.A. Hoffer and G.B. Jenne. United States Patent Application 20050118887 filed June 3, 2004, published June 2, 2005.

10. Nerve Cuff having One or More Isolated Chambers. Canadian Patent No. No. 2,300,968 awarded to J.A. Hoffer, Y. Chen, K. Strange and P. Christensen, on December 19, 2006.

11. Methods and apparatus for harvesting biomechanical energy. J.M. Donelan, A.D. Kuo, J.A. Hoffer. Q. Li and D. Weber. PCT/CA2006/001302 filed 10 Aug 2006, published 15 Feb 2007.

12. Nerve Cuff having One or More Isolated Chambers. J.A. Hoffer, Y. Chen, K. Strange and P. Christensen. Japan Patent No. 4,026,168 issued October 19, 2007.

13. Electrical stimulation system and methods for treating phantom limb pain and for providing sensory feedback to an amputee from a prosthetic limb. J.A. Hoffer. U.S. Patent No. 7,302,296 awarded November 27, 2007.

14. Implantable modular, multi channel connector system for nerve signal sensing and electrical stimulation applications. J.A. Hoffer and G. Jenne. U.S. Patent No.7,303,422 awarded December 4, 2007.

15. Nerve Cuff, Method and Apparatus for Manufacturing Same. Hoffer, Joaquin Andres; Imbeau Marc-Olivier; Vallieres Jean-Martin. P.C.T. application No. WO2007/140597, published December 13, 2007.

16. Methods and apparatus for harvesting biomechanical energy. Donelan, J.M., Kuo, A.D., Hoffer, J.A., Li, Q., and Weber, D.J. U.S. patent application 20080278028 filed April 30, 2008, published November 13, 2008.

17. Methods and apparatus for harvesting biomechanical energy. Donelan, J.M., Kuo, A.D., Hoffer, J.A., Li, Q., and Weber, D.J. U.S. patent application 20080277943 filed April 30, 2008, published November 13, 2008.

18. Transvascular Nerve Stimulation Apparatus and Methods. Hoffer, Joaquin Andres. P.C.T. application No. WO2008/092246, published August 7, 2008.

Current Funding

Minimally Invasive Nerve Stimulation Electrode. NSERC I2I (Idea-to-Innovation) prototype development/proof of concept grant. J.A. Hoffer, P.I.

Research Projects

Quantitative Imaging of Peripheral Nerves

Biomechanical Energy Harvester
Neurostepâ„¢ implanted assistive system for walking

Selected Publications

Initial results with fully implanted NeurostepTM FES system for foot drop.
July 5, 2005
Hoffer JA, Baru M, Bedard S, Calderon E, Desmoulin G, Dhawan P, Jenne G, Kerr J, Whittaker M, Zwimpfer TJ, in: 10th Annual Conference of the International FES Society, Montreal, Canada

Chronically implanted epineural electrodes for repeated assessment of nerve conduction velocity and compound action potential amplitude in rodents.
2004
Murphy, B., Krieger, C. and Hoffer, J.A., J. Neurosci. Methods 132:25-33.

How to use nerve cuffs to stimulate, record or modulate neural activity.
2001
Hoffer, J.A. and K. Kallesøe, Chapter 5 in "Neural Prostheses for Restoration of Sensory and Motor Function", K.A. Moxon and J.K. Chapin, Eds., CRC Press, pp. 139-175.

Nerve cuffs for nerve repair and regeneration.
2000
Hoffer, J.A. and K. Kallesøe, Progr. Brain Res. 128:121-134.

Restoration of use of paralyzed limb muscles using sensory nerve signals for state control of FES-assisted walking.
1999
Strange, K. and Hoffer, J.A., IEEE Trans. Rehab. Engineering 7:289-300.

Gait phase information provided by sensory nerve activity during walking: applicability as state controller feedback for FES.
1999
Strange, K. and Hoffer, J.A., IEEE Trans. Biomed. Engineering 46:797-809.

Regional variability of stretch reflex amplitude in the cat medial gastrocnemius muscle during a postural task.
1997
Eng, J.J. and Hoffer, J.A., J. Neurophysiol 78:1150-1154.

Neural signals for command control and feedback in functional neuromuscular stimulation: a review.
1996
Hoffer, J.A., Stein, R.B., Haugland, M., Sinkjær, T., Durfee, W.K., Schwartz, A.B., Loeb, G.E. and Kantor, C. J. Rehab. Res. & Dev. 33:145-157.

Artifact-free sensory nerve signals obtained from cuff electrodes during functional electrical stimulation of nearby muscles.
1994
Haugland, M. and Hoffer, J.A., IEEE trans. Rehab. Engng. 2:37-40.

Slip information provided by nerve cuff signals: application in closed-loop control of functional electrical stimulation.
1994
Haugland, M. and Hoffer, J.A., IEEE trans. Rehab. Engng. 2:29-36.

Skin contact force information in sensory nerve signals recorded by implanted cuff electrodes.
1994
Haugland, M., Hoffer, J.A. and Sinkjær, T., IEEE Trans. Rehab. Engng. 2:18-28.

Velocity of ultrasound in active and passive cat medial gastrocnemius muscle.
1992
Caputi, A.A., Hoffer, J.A. and Pose, I.E., J. Biomech. 25: 1067-1074.

Factors determining segmental reflex action in normal and decerebrate cats.
1990
Sinkjær, T. and Hoffer, J.A., J. Neurophysiol. 64: 1625-1635.

Segmental reflex action in normal and decerebrate cats.
1990
Hoffer, J.A., Leonard, T.R., Cleland, C.L. and Sinkjær, T., J. Neurophysiol. 64: 1611-1624.

Roles of muscle activity and load on the relationship between muscle spindle length and whole muscle length in the freely walking cat.
1989
Hoffer, J.A., Caputi, A.A., Pose, I.E. and Griffiths, R.I., Progr. Brain Res. 80: 75-85.

Biomechanical energy harvesting: generating electricity during walking with minimal user effort.
February 8, 2008
J. M. Donelan, Q. Li, V. Naing, J.A. Hoffer, D.J. Weber and A.D. Kuo. Biomechanical energy harvesting: generating electricity during walking with minimal user effort. Science 319: 807-810, 2008.

Kerr, J. and Hoffer, J.A. Feasibility of using implanted neurosensors to monitor displacement of the center-of-pressure during postural sway in paraplegic subjects. Int’l. Functional Electrical Stimulation Soc., 11th Ann. Conf., Zao, Japan, pp 88-90, 2006.
September 13, 2006
Kerr, J. and Hoffer, J.A. Feasibility of using implanted neurosensors to monitor displacement of the center-of-pressure during postural sway in paraplegic subjects. Int’l. Functional Electrical Stimulation Soc., 11th Ann. Conf., Zao, Japan, 2006.

Estimation of Nerve Dimensions from MRI of the Human Thigh.
December 22, 2008
J.A. Hoffer, E. Gibson, B. Mädler, M.F. Beg. Estimation of Nerve Dimensions from MRI of the Human Thigh. Int’l. Functional Electrical Stimulation Soc., 13th Ann. Conf., Freiburg, Germany, Sept. 2008.

Corrosion Resistance of Stainless Steel Nerve Cuff Electrodes in the NeurostepTM FES System.
November 12, 2007
Cogan SF, Atsma WJ, Hoffer JA, Levesque D. Corrosion Resistance of Stainless Steel Nerve Cuff Electrodes in the NeurostepTM FES System. Int’l. Functional Electrical Stimulation Soc., 12th Ann. Conf., Philadelphia, PA, USA, Nov. 2007.

Estimation of Nerve Dimensions from MRI of the Human Thigh.
September 23, 2008
J.A. Hoffer, E. Gibson, B. Mädler, M.F. Beg. Estimation of Nerve Dimensions from MRI of the Human Thigh. Int’l. Functional Electrical Stimulation Soc., 13th Ann. Conf., Freiburg, Germany, Sept. 2008.