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Matthias J. Krenn, PhD

Education 

• 2015 - Medical University of Vienna, Vienna, Austria 
  Doctoral Program of Applied Medical Science – Biomedical engineering (PhD) 
  Thesis: Electrical stimulation training to improve neuromuscular performance in sedentary elderly. 
• 2007 - Vienna University of Technology, Vienna, Austria 
  Master’s degree in electrical engineering (MSc) 
  Thesis: Dynamic of the contraction of electrical stimulated anterior thigh muscles at higher stimulation frequencies measured with accelerometers. 

Research keywords 

• Neuromodulation, electrical stimulation 
• Neurorehabilitation; spinal cord injury; traumatic brain injury 
• Spinal motor control of lower extremities 
• Biomedical engineering 

Research projects 

Spinal motor control 

A spinal cord injury (SCI) separates the neural circuitry in the spinal cord responsible for leg movements from normal brain control. However, below the level of injury, sensory feedback to the spinal cord is uninjured, which still gives us access to the neural circuity for stepping. 

Attempts have been made to stimulate sensory inputs to the spinal cord to enhance stepping function in people with SCI, but these have had variable results. One reason for this may be that the spinal neural circuits for stepping may be in different functional states in the face of spinal cord injuries. Our goal is to understand the neurophysiological profile of spinal cord injuries to augment stepping in individuals or groups of individuals. 

In our studies, we propose to use electrical stimulation of sensory nerve fibers at the spinal level (transcutaneous spinal stimulation) for studying spinal reflexes under several test conditions during robotic-assisted stepping. We anticipate discovering different neurophysiological profiles that can be explained by the pattern and severity of SCI, which will predict the responsiveness of different individuals to neuromodulation with transcutaneous spinal stimulation. This could serve to improve the magnitude of the effect of neuromodulation in patients for this novel neurorehabilitation approach. 

Neurorehabilitation engineering 

Biomedical engineering developments, including sensor and measurement technology, biomechanical instrumentation, with a strong focus to electrical stimulation for nervous and muscular tissue.
Bridging to external academic and industrial expertise and partnership, from research collaboration to application transfer of novel product solutions and methodologies. 

Selected publications 

• Krenn MJ, Vargas Luna JL, Mayr W, Stokic DS (2020) Bipolar transcutaneous spinal stimulation evokes short-latency reflex responses in human lower limbs alike standard unipolar electrode configuration., Journal of Neurophysiology 
• Krenn M, Perry BE, Chow JW, Tansey KE (2019). Using a robot-assisted gait orthosis to assess lower limb performance in neurorehabilitation. Biomedical Sciences Instrumentation 
• Vargas-Luna JL, Krenn M, Mayr W, Cortes Ramirez JA (2017). Optimization of interphase intervals to enhance the evoked muscular responses of transcutaneous neuromuscular electrical stimulation. Artificial Organs. 41(12):1145-1152 
• Dimitrijevic MR, Krenn M, Mayr W, McKay B (2016). Human spinal cord motor control that is partially or completely disconnected from the brain. American Journal of Neuroprotection and Neuroregeneration, 8:1–15 
• Mayr W, Krenn M, Dimitrijevic MR (2016). Epidural and transcutaneous spinal electrical stimulation for restoration of movement after incomplete and complete spinal cord injury. Current Opinion in Neurology, 29(6):721–726 
• Krenn M, Hofstoetter US, Danner SM, Minassian K, Mayr W (2015). Multi-electrode array for transcutaneous lumbar posterior-root stimulation. Artificial Organs, 39(10):834–40 

Full list of publications at ORCID or PubMed. 

Funding 

• Wings for Life USA - Spinal Cord Research Foundation, Inc. (link to Wings for Life; opens in new window) 
  Defining the capacity of the lumbosacral network for neuromodulation in humans with spinal cord injury; WFL-US-07/19 
  Duration: July 1, 2019 – June 30, 2021 
  Role: Principal investigator 
• Cooperative research program funded by MED-EL, Innsbruck, Austria (link to MED-EL; opens in new window) 
  Functional electrical stimulation and neuromodulation. 
  Duration: March 1, 2017 – August 31, 2017 
  Role: Investigator