The Efficacy of Cognitive Intervention Programs for Mild Cognitive Impairment: A Systematic Review.

Mild cognitive impairment (MCI) describes a transitional state in progression from normal aging to dementia, especially Alzheimer's disease (AD). Currently, there is no effective pharmacological treatment that offers a long-term beneficial effect to delay the progression to dementia. There is growing evidence that supports an important role of non-pharmacological cognitive interventions. Therefore, it is warranted to clarify the distinct forms of cognitive interventions and their effects based on previous clinical trials. We aimed to provide a review of clinical trials of non-pharmacological cognitive interventions for MCI and to address the characteristics of the study patients, cognitive intervention programs and short-term / long-term benefits of the interventions. A total of 32 articles were identified according to the inclusion criteria. The results showed positive effects for both objective and subjective outcome variables, and these effects persisted from 1 month up to 5 years. Although many of the positive effects were related to improvement in trained tasks, alterations in neuroimaging and the transfer effects shown by some studies are encouraging. Future research in this area requires a larger sample size with a wider spectrum of MCI, more instructive outcome measures and a longer follow up duration. Keywords: Alzheimer's disease, cognitive intervention, cognitive outcome, functional brain imaging, mild cognitive impairment, progression.