Lateral Corticospinal Tract Damage Correlates With Motor Output in Incomplete Spinal Cord Injury

Objective: To investigate the relationship between spinal cord damage and specific motor function in participants with incomplete spinal cord injury (iSCI). Design: Single-blinded, cross-sectional study design. Setting: University setting research laboratory. Participants: Individuals with chronic cervical iSCI (N=14; 1 woman, 13 men; average age ± SD, 43±12y). Interventions: Not applicable. Main Outcome Measures: Axial T2-weighted magnetic resonance imaging (MRI) of spinal cord damage was performed in 14 participants with iSCI. Each participant's damage was processed for total damage quantification, lateral corticospinal tract (LCST) and gracile fasciculus (GF) analysis. Plantarflexion and knee extension were quantified using an isokinetic dynamometer. Walking ability was assessed using a 6-minute walk test. Results: Total damage was correlated with plantarflexion, knee extension, and distance walked in 6 minutes. Right LCST damage was correlated with right plantarflexion and right knee extension, while left LCST damage was correlated with left-sided measures. Right and left GF damage was not correlated with the motor output measures. Conclusions: MRI measures of spinal cord damage were correlated to motor function, and this measure appears to have spatial specificity to descending tracts, which may offer prognostic value after SCI.