Spinal plasticity in robot-mediated therapy for the lower limbs

Area of Science:

• Neuroscience
• Rehabilitation Engineering
• Biomedical Engineering

Background:

• Robot-mediated therapy offers potential for enhancing walking post-central nervous system (CNS) injury.
• Current understanding of the neural mechanisms, especially spinal cord changes, driving functional recovery from robotic therapy is limited.
• Variability in patient response highlights the need to investigate underlying mechanisms like spinal plasticity.

Purpose of the Study:

• To review existing literature on spinal plasticity induced by robotic training in humans.
• To propose methods for measuring spinal plasticity using robotic devices.
• To explore the potential of robotic devices for routine spinal circuitry assessment.

Main Methods:

• Review of recent scientific literature on robotic-assisted therapy and spinal plasticity.
• Analysis of studies using body weight-supported (BWS) robotic-assisted step training in spinal cord injury (SCI) and stroke patients.
• Examination of reflex pathway modulation (e.g., H-reflex, stretch reflexes) as indicators of spinal changes.

Main Results:

• Evidence suggests robotic training, specifically BWS robotic-assisted step training, induces changes in spinal reflex pathways in lower limbs.
• SCI patients undergoing BWS robotic training demonstrated re-emergence of physiological phase modulation of the soleus H-reflex during walking.
• Stretch reflexes elicited by joint rotations are identified as a promising tool for probing spinal circuitry.

Conclusions:

• Robotic-assisted training can induce measurable spinal plasticity, contributing to functional improvements in patients with CNS injuries.
• Integrating stretch reflex elicitation technology into robotic devices could enable routine assessment of spinal circuitry during rehabilitation.
• Further development of robotic systems is recommended to facilitate comprehensive evaluation of spinal plasticity alongside therapeutic interventions.