Characterization of motor-evoked responses obtained with transcutaneous electrical spinal stimulation from the lower-limb muscles after stroke

Yaejin Moon, Taylor Zuleger, Martina Lamberti, Ashir Bansal, Chaithanya K. Mummidisetty, Kelly A. McKenzie, Lindsey Yingling, Sangeetha Madhavan, Elliot J. Roth, Richard L. Lieber, Arun Jayaraman*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

An increasing number of studies suggests that a novel neuromodulation technique tar-geting the spinal circuitry enhances gait rehabilitation, but research on its application to stroke survivors is limited. Therefore, we investigated the characteristics of spinal motor-evoked responses (sMERs) from lower-limb muscles obtained by transcutaneous spinal cord stimulation (tSCS) after stroke compared to age-matched and younger controls without stroke. Thirty participants (ten stroke survivors, ten age-matched controls, and ten younger controls) completed the study. By using tSCS applied between the L1 and L2 vertebral levels, we compared sMER characteristics (resting motor threshold (RMT), slope of the recruitment curve, and latency) of the tibialis anterior (TA) and medial gastrocnemius (MG) muscles among groups. A single pulse of stimulation was delivered in 5 mA increments, increasing from 5 mA to 250 mA or until the subjects reached their maximum tolerance. The stroke group had an increased RMT (27–51%) compared to both age-matched (TA: p = 0.032; MG: p = 0.005) and younger controls (TA: p < 0.001; MG: p<0.001). For the TA muscle, the paretic side demonstrated a 13% increased latency compared to the non-paretic side in the stroke group (p = 0.010). Age-matched controls also exhibited an increased RMT compared to younger controls (TA: p = 0.002; MG: p = 0.007), suggesting that altered sMER characteristics present in stroke survivors may result from both stroke and normal aging. This observation may provide implications for altered spinal motor output after stroke and demonstrates the feasibility of using sMER characteristics as an assessment after stroke.

Original languageEnglish (US)
Article number289
Pages (from-to)1-14
Number of pages14
JournalBrain Sciences
Volume11
Issue number3
DOIs
StatePublished - Mar 2021

Keywords

  • Electrical spinal cord stimulation
  • Spinal cord
  • Spinal motor-evoked response
  • Stroke

ASJC Scopus subject areas

  • Neuroscience(all)

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