Decreased white matter fractional anisotropy is associated with poorer functional motor skills following spinal cord injury: a pilot study.

STUDY DESIGN

Prospective cross-sectional study OBJECTIVES: The objective of this study was to assess associations between white matter changes and functional motor markers including grip strength and prehension in the upper limb.

SETTING

Single Center Imaging Study, in Vancouver Canada.

METHODS

Diffusion tensor imaging produced FA (Fractional Anisotropy) maps of the brain for participants with SCI (n = 7) and controls (n = 6). These FA maps were analyzed using tract-based spatial statistics. Correlations between the FA values (of the genu of the corpus callosum, the left superior longitudinal fasciculus and the right anterior thalamic radiation) of the SCI group and functional outcomes (grip strength, Graded Redefined Assessment of Strength, Sensibility and Prehension (GRASSP)) were assessed.

RESULTS

Significant differences (p < 0.05) were found between the FA values of the controls and the SCI group in two white matter clusters, with lower values in the SCI group. Strong correlations were found between the FA values of the identified clusters and the age of SCI participant, and the right GRASSP Quantitative Prehension and right total GRASSP score.

CONCLUSIONS

This preliminary data suggests that decreased FA in the genu of the corpus callosum may be a biomarker for functional motor ability of the upper limb with higher FA indicating better ability. Further research needs to be done to determine if other white matter tracts are also associated with strength and use of the hand following SCI.

SPONSORSHIP

The International Collaboration on Repair Discoveries (operating grant) and Canada Research Chair Program (for JJE) provided support for this research.