Distinct Patterns of Spasticity and Corticospinal Connectivity Following Complete Spinal Cord Injury

Following spinal cord injury (SCI), the excitability of neuronal networks below the injury increases to compensate for the loss of corticospinal neurons, leading to the development of spasticity. This study found three subgroups of SCI patients: those with spasticity in both quadriceps and soleus, those with spasticity only in the quadriceps, and those with no spasticity in either muscle. The presence of spasticity can help predict the degree of residual connection between the brain and muscles after a severe spinal cord injury.

• 1
  Three distinct sub-groups of people with SCI were identified: participants with spasticity and corticospinal responses in the quadriceps femoris and soleus muscle, participants with spasticity and corticospinal responses in the quadriceps femoris muscle only, and participants with no spasticity or corticospinal responses in either muscle.
• 2
  While cortical MEPs were present only in the quadriceps in participants with spasticity, thoracic MEPs were present in quadriceps and soleus when spasticity was present, suggesting that direct activation of corticospinal axons represents a more sensitive outcome to assess residual corticospinal connectivity.
• 3
  Cortical and thoracic MEP amplitudes correlated with the degree of spasticity.