Several studies have shown that cognitive intervention may be beneficial for people with Alzheimer disease (AD), but literature reviews conducted so far, have yielded mixed and inconclusive results. In this work, through an extensive bibliographic search, we aim: (1) to analyze the efficacy of cognitive intervention in patients diagnosed with AD; (2) to provide an estimate of the feasibility of cognitive intervention; and (3) to review available cost-effectiveness data of this approach. Four randomized controlled trials of cognitive intervention, for patients diagnosed with AD that incorporated cognitive intervention and mock intervention control conditions, were included in the analysis. Only the domain of global cognitive functioning, as measured by Mini-Mental State Examination, showed significant intervention effects. No effects were observed in the remaining domains. Concerning feasibility, high rates of completion and adherence were found. A single randomized controlled trial, with unspecified dementia, suggested cognitive intervention to be cost-effective. Given the currently available dearth of well-controlled and focused trials in AD, these results should be carefully interpreted and remain to be confirmed in the future. There is a clear need for more high-quality research.