Treadmill measures of ambulation rates in ovine models of spinal cord injury and neuropathic pain

Abstract

Our laboratories are developing treadmill-based gait analysis employing sheep to investigate potential efficacy of intra-dural spinal cord stimulation in the treatment of spinal cord injury and neuropathic pain. As part of efforts to establish the performance characteristics of the experimental arrangement, this study measured the treadmill speed via a tachometer, video belt-marker timing and ambulation-rate observations of the sheep. The data reveal a 0.1–0.3% residual drift in the baseline (unloaded) treadmill speed which increases with loading, but all three approaches agree on final speed to within 1.7%, at belt speeds of ≈4 km/h. Using the tachometer as the standard, the estimated upper limit on uncertainty in the video belt-marker approach is ± 0.18 km h⁻¹ and the measured uncertainty is ± 0.15 km h⁻¹. Employment of the latter method in determining timing differences between contralateral hoof strikes by the sheep suggests its utility in assessing severity of SCI and responses to therapeutic interventions.

Keywords:

• Spinal cord
• spinal cord stimulator
• in vivo models
• treadmill
• ambulation rates

Acknowledgements

We thank our University of Iowa colleagues H. Chen, S. Viljoen, MD, and B. D. Dalm, MD, for technical assistance and their interest in this work.

Disclosure statement

Reddy, Gillies and Howard may receive patent royalties from the commercial license of the intellectual properties for intra-dural spinal cord stimulation negotiated by their respective institutions. Gillies and Howard hold equity in the licensee and serve on its Board of Directors, respectively.