Sarcopenia is a condition characterized by a decrease in muscle mass and function (strength and mobility) that is frequently observed in the elderly. In people with paresis and altered mobility due to central nervous system (CNS) diseases, this definition then may not be applicable. In CNS diseases, mainly stroke and spinal cord injury, different and specific patterns of muscle loss and muscle changes have been described, due to denervation, disuse atrophy, spasticity and myosteatosis. The main observations available about these phenomena in CNS diseases are reviewed, and a broad view on the specific physiopathological mechanisms is also described. Moreover, a description of the potential pharmacological targets and treatment strategies (physical and nutritional) is provided. Since sarcopenia of the elderly and muscle modifications and muscle atrophy in CNS diseases have different mechanisms, it is probable that they do not respond equally to the same treatments.