The disclosure relates to methods and compositions for preventing or treating cognitive dysfunction. The methods comprise administering an effective amount of an aromatic-cationic peptide to subjects in need thereof. Specifically, the aromatic-cationic peptide has the formula D-Arg-2′,6′-Dmt-Lys-Phe-NH2, and the cognitive dysfunction is associated with a reduced cerebral metabolic rate of oxygen (CMRO).