Vibration Training after Chronic Spinal Cord Injury: Evidence for Persistent Segmental Plasticity

This study investigates whether vibration training can restore H-reflex paired-pulse depression in individuals with chronic, complete SCI. H-reflex paired-pulse depression is typically lost after SCI, reflecting reorganization of spinal interneurons due to loss of cortical inhibition. The study aims to determine if long-term vibration training can induce neuroplasticity in segmental reflex pathways. Participants received twice-weekly vibration training to one lower limb, with the other limb serving as a control. H-reflex testing was conducted before, during, and after vibration sessions to assess changes in H-reflex depression. The study hypothesized that vibration training would restore H-reflex depression in the trained limb. The results showed that the trained limbs exhibited H-reflex depression values comparable to those of acute SCI and non-SCI individuals, while the untrained limbs showed values similar to chronic SCI. This suggests that vibration training can initiate a return of H-reflex depression, indicating persistent plasticity in spinal reflex pathways even after long-term SCI.

• 1
  Trained limbs of all five participants showed H-reflex depression values within the range of acute SCI and non-SCI H-reflex depression.
• 2
  The average difference in H-reflex depression between trained and untrained limbs was 34.98% during vibration, which was statistically significant.
• 3
  Untrained limbs demonstrated H2 depression similar to chronic SCI, while trained limbs demonstrated H2 depression similar to acute SCI.