Adaptive control of movement for neuromuscular stimulation-assisted therapy in a rodent model

Seung Jae Kim, Mallika D. Fairchild, Alexandre Iarkov, James Abbas, Ranu Jung

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Neuromotor therapy after spinal cord or brain injury often attempts to utilize activity-dependent plasticity to promote functional recovery. Neuromuscular electrical stimulation that activates paralyzed or paretic muscles may enhance passive assistance therapy by activating more muscle mass and enriching the sensory pattern with appropriately timed muscle spindle activation. To enable studies of activity-dependent plasticity, a rodent model for stimulation-assisted locomotor therapy was developed previously. To be effective, however, such a system must allow lengthy sessions of repetitive movements. In this study, we implemented an adaptive pattern generator/pattern shaper (PG/PS) control system for a rodent model of neuromotor therapy and evaluated its ability to generate accurate and repeatable hip movements in lengthy sessions by adjusting the activation patterns of an agonist/antagonist muscle pair. In 100-cycle movement trials, the PG/PS control system provided excellent movement tracking (10% error), but stimulation levels steadily increased to account for muscle fatigue. In trials using an intermittent movement paradigm (100 sets of five-cycle bouts interspersed by 20-s rest periods), excellent performance (8% error) was also observed with less stimulation, thus indicating reduced muscle fatigue. These results demonstrate the ability of the PG/PS control system to utilize an agonist/antagonist muscle pair to control movement at a joint in a rodent model. The demonstration of repeatable movements over lengthy intermittent sessions suggests that it may be well suited to provide efficient neuromotor therapy.

Original languageEnglish (US)
Article number4671120
Pages (from-to)452-461
Number of pages10
JournalIEEE Transactions on Biomedical Engineering
Issue number2
StatePublished - Feb 2009


  • Activity-dependent plasticity
  • Adaptive neural network control
  • Intramuscular electrodes
  • Locomotor therapy
  • Neuromuscular stimulation
  • Spinal cord injury (SCI)

ASJC Scopus subject areas

  • Biomedical Engineering


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