Methylation analysis in a subset of a total of 200 patients (114 patients with dementia, of whom 31 had severe cognitive impairment, and 86 patients with MCI) revealed that the differences in methylation of 6 chosen regions in BDNF promoters and exon IX were not statistically significant between individuals with dementia and MCI (Figure 1, Supplementary Table S2). This evidence concerns the gene BDNF and Cognitive impairment.