Zivadinov R, et al. - This longitudinal study intended to examine the effect of switching from glatiramer acetate (GA) 20 mg/daily to GA 40 mg × 3/weekly on the evolution of microstructural changes in the thalamus and normal appearing white matter (NAWM), using diffusion tensor imaging (DTI). It was established that GA 40 mg × 3/weekly displayed a comparable effect to GA 20 mg/daily on the DTI measures over 34 months.