A recent meta-analysis that included over 29.000 individuals found that the odds ratio (OR) of individuals with high brain reserve compared to low was 0.54 (p < 0.0001), a risk decrease of 46%. Among the factors that influence cognitive reserve, mentally stimulating activities was the most robust factor after controlling for education, age, occupation and other potential confounds. The brain reserve effect was sustained over a median longitudinal follow-up of 7 years. It would be interesting to detect whether a complex cognitive training could show similar effects on the cognitive abilities of patients with mild Alzheimer's disease (AD) and mild cognitive impairment (MCI) as it has been reported in previous studies based on mentally stimulating activities analysis.