Abstract
Study design
Pilot study (case series).
Objective
The objective of this study was to establish spinal neurophysiological changes following high-frequency transspinal stimulation during robot-assisted step training in individuals with chronic motor complete spinal cord injury (SCI).
Setting
University research laboratory (Klab4Recovery).
Methods
Four individuals with motor complete SCI received an average of 18 sessions of transspinal stimulation over the thoracolumbar region with a pulse train at 333 Hz during robotic-assisted step training. Each session lasted ~1 h, with an average of 240 stimulations delivered during each training session. Before and after the combined intervention, we evaluated the amplitude modulation of the long-latency tibialis anterior (TA) flexion reflex and transspinal evoked potentials (TEP) recorded from flexors and extensors during assisted stepping, and the TEP recruitment curves at rest.
Results
The long-latency TA flexion reflex was depressed in all phases of the step cycle and the phase-dependent amplitude modulation of TEPs was altered during assisted stepping, while spinal motor output based on TEP recruitment curves was increased after the combined intervention.
Conclusion
This is the first study documenting noninvasive transspinal stimulation coupled with locomotor training depresses flexion reflex excitability and concomitantly increases motoneuron output over multiple spinal segments for both flexors and extensors in people with motor complete SCI. While both transspinal stimulation and locomotor training may act via similar activity-dependent neuroplasticity mechanisms, combined interventions for rehabilitation of neurological disorders has not been systematically assessed. Our current findings support locomotor training induced neuroplasticity may be augmented with transspinal stimulation.
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Data availability
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Funding
Research reported in this publication was supported by the Spinal Cord Injury Research Board (SCIRB) of the New York State Department of Health (NYSDOH) via C32248GG and C32095GG contracts, and in part by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH) under award number R01HD100544 awarded to MK. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the paper.
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MZ: EMG data analysis, developed figures, and wrote the first draft of the paper. TSP performed experiments, contributed to paper writing and reviewing. MK formulated the hypotheses, designed the experiments, performed experiments and analysis, and contributed to paper writing and reviewing.
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Zaaya, M., Pulverenti, T.S. & Knikou, M. Transspinal stimulation and step training alter function of spinal networks in complete spinal cord injury. Spinal Cord Ser Cases 7, 55 (2021). https://doi.org/10.1038/s41394-021-00421-6
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DOI: https://doi.org/10.1038/s41394-021-00421-6
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