Alzheimer disease (AD) is one of the most prevalent chronic medical conditions affecting the elderly population. The effectiveness of approved antidementia drugs, however, is limited-licensed AD medications provide only moderate relief of clinical symptoms. Cognitive intervention is a noninvasive therapy that could aid prevention and treatment of AD. Data suggest that specifically designed cognitive interventions could impart therapeutic benefits to patients with AD that are associated with substantial biological changes within the brain. Moreover, evidence indicates that a combination of pharmacological and non-pharmacological interventions could provide greater relief of clinical symptoms than either intervention given alone. Functional and structural MRI studies have increased our understanding of the underlying neurobiological mechanisms of aging and neurodegeneration, but the use of neuroimaging to investigate the effect of cognitive intervention on the brain remains largely unexplored. This Review provides an overview of the use of cognitive intervention in the healthy elderly population and patients with AD, and summarizes emerging findings that provide evidence for the effectiveness of this approach. Finally, we present recommendations for future research on the use of cognitive interventions in AD and discuss potential effects of this therapy on disease modification.