To understand microstructural changes associated with healthy aging, multi-shell diffusion-weighted images were acquired in a group of 71 cognitively normal volunteers (31-young, 40-old). Signal representation and tissue specific models were used to assess relationship between age and WM microstructural changes. TBSS was performed for group-comparison. Results showed that FA and NODDI-based indices exhibited highest degree of sensitivity with overlap in much wider regions. The results also showed regional differences among FA and ODI. The influence of DKI was more regionalized and complemented by FA. The study demonstrated the sensitivity of higher-order models to the age-related changes in tissue microstructure.