1. Electrical impedance myography ( and a little MUNE) Seward B. Rutkove, MD Beth Israel Deaconess Medical Center Harvard Medical School

2. Disclosures 1.Consultant and equity in Convergence Medical Devices, Inc. 2.Consulting for Neuralstem, Inc., 3.Two patent applications in electrical impedance 4.Grant funding from NIH, ALSA Association, the Spinal Muscular Atrophy Foundation, and NASA.

3. Electrical impedance testing? The assessment of characteristics of a material by measuring changes to an applied electrical current Used in forestry, metallurgy, geology

4. But also in humans… Whole body bioimpedance analysis – Total body water/fat Electrical impedance tomography – Imaging Electrical impedance mammography (also EIM) – Breast cancer detection Electrical impedance dermography

5. Electrical impedance myography The broad hypothesis: Alterations in composition and structure of muscle with disease will impact the electrical impedance of muscle in unique and reproducible ways.

6. Different disorders, different pathologies Normal Neurogenic Myopathy/Dystrophy Disuse Atrophy

7. Measured voltage amplitude is proportional to muscle resistance (R) Tissue reactance (X), related to capacitance, causes shift in timing Electrical impedance in healthy muscle Applied electrical current Measured voltage Voltmeter Current Generator

8. Reduced tissue Reactance (X) causes reduced shift in timing Increased tissue Resistance (R) causes higher amplitude voltage Applied electrical current Measured voltage Phase will decrease Phase = arctan(X/R) Electrical impedance in diseased muscle Voltmeter Current Generator From neuromuscular.wustl.edu

9. Off-the-shelf bioimpedance devices Single Frequency Multifrequency Useful, but limited

10. Instrumentation: Past and Present 2001 2005 2009

11. On the animal front

12. Phase (degrees) Resistance (ohms) What we measure Reactance (ohms)

13. Raw muscle data Gives us the capability of relating surface data to intrinsic muscle data and vice versa Measure muscle conductivity and permittivity

14. Conductivity and permittivity plots Ahad et al, 2009

15. Repeatability RatsMice Healthy ALS CMD system-humans Adhesive electrodes-humans

16. Current Data? – ALS – SMA – DMD – Sarcopenia – Nerve injury (radiculopathy, crush models) – AMN

17. Follow-up ALSA-funded study Patient visits approximately 3 months apart (a total of 5 visits over 1 year) 8 Sites involved, 60 patients EIM measurements performed on Biceps, wrist extensors, abductor pollicis brevis, quadriceps, and tibialis anterior Intra-session repeatability on biceps Also performed handheld dynamometry, ALSFRS, MUNE Major EIM outcome measure: –Rate of decline in 50 kHz phase

18. Results: In patient terms for 6 month trial Assuming 6 month, placebo-controlled trial, 3 measurements, 20% treatment effect, p < 0.05, one-sided

19. Neuralstem study Glass et al, 2012, Stem Cells

20. ALS Rat Data: Measuring Disease Progression 16 animals followed from pre-symptomatic to death Early Advanced Early Advanced Early Advanced Wang et al, 2011

21. SOD1 g93a ALS rat data Wang et al, 2011

22. As a biomarker in spinal muscular atrophy Natural history study of EIM in SMA, funded by SMA Foundation – Collaborative effort with Children’s Hospital Boston, Dr. Basil Darras – 28 SMA children mean age 9.6 years, followed for mean of 16 months – 20 Normal children enrolled, mean age 9.8 years, followed for mean of 17 months – Mainly Type 2 and Type 3 children

23. SMA Multifrequency Data

24. SMA cross-sectional data Type 2 Type 3 healthy

25. SMA in older kids: no active motor neuron loss, but no muscle growth either Healthy kids From Rutkove et al, 2012 Healthy SMA P = 0.018

26. Primary muscle disease Tarulli et al, 2006

27. Preliminary DMD data:

28. Quantitative Ultrasound and EIM in DMD (QED) Funded by NIH/NIAMS fall 2011 Basil Darras, MD: Co-PI Enrolling 35 healthy kids and 35 with DMD and follow over 2 years Frequent measurements early on; less frequent later Started recruiting in March; about 17 DMD boys and 15 healthy boys already recruited

29. Sarcopenia From Aaron et al, 2006 Quadriceps Tibialis anterior

30. EIM in 4 healthy older subjects over a several year period From Aaron et al, 2006 Quadriceps Two subjects overlap

31. And sensitive to improvement too… Improvement in EIM data upon returning to normal activity after recovery from ankle fracture From Tarulli et al, 2009 Open circles, immediately after injury Closed circles, upon partial or full recovery Lower limit of normal Mean Value

32. Hind Limb Suspension studies in rats and mice: A model for assessing sarcopenia and disuse

33. EIM phase declines and recovers with hind limb suspension N = 45

34. Relationship between phase and muscle fiber size

35. What does it mean? Is correlation sufficient? How do we an answer the question? – Animal models? – Tissue culture studies? – Single cell studies?

36. Thanks Physicists and Engineers Carl Shiffman, PhD Ronald Aaron, PhD Joel Dawson, PhD Jacob White, PhD Physician researchers Andrew Tarulli, MD Basil Darras, MD Pushpa Narayanaswami, MD Jeremy Shefner, MD, PhD Ted Burns, MD (also for wine) Mary Bouxsein, PhD Jonathan Bean, MD Jonathan Glass, MD Eva Feldman, MD, PhD Jim Caress, MD Michael Benatar, MD Research Staff Mohammad Ahad, PhD Jia Li, PhD Lucy Wang Phil Mongiovi Minhee Sung Mina Jafarpoor Lindsay Garmirian Anne Chin Andrew Spieker Convergence Medical Devices Jose Bohorquez, PhD Mike Rinehart, PhD Neil Lupton, PhD Laura Freeman, RN

37. Funding R01 NS055099; R01 AR060850; K24 NS060951