Discussion

Fractional anisotropy is highly sensitive to microstructural changes, with lower FA values indicating possible damage in the WM tracts. In the motor tracts, the only significant difference between the AD group and healthy controls, was in the right corticospinal tract where FA was surprisingly higher in the AD group, but only along 10% of the region of interest along the tract. However, MD values indicate that there is possibly more necrosis in the AD patient's motor tracts. 
Similarly, in the non-motor tracts there are relatively no differences in the FA values, however the MD values indicate possible problems in the AD group. When comparing the percent of each ROI where there is indicated difference, there appears to more damage in the non-motor tracts than the motor tracts.
With very little difference in the FA values between groups, it would seem that gait impairments may not be due to damage in the direct motor pathways, but perhaps in the association pathways or GM. However, based on MD values we might investigate the thalamic radiations for their possible role in gait impairment.
A significant limitation in this project is the assumption that the AD group in this study exhibit gait impairment. There is no data reported to support this assumption.