INS and type 2 diabetes mellitus: Moreover, epidemiological studies have demonstrated that both type 1 diabetes (insulin-deficient, T1DM) and type 2 diabetes (insulin-resistant, T2DM) are co-morbid with cognitive impairment, including dementia and Alzheimer’s disease (AD) (Umegaki, 2010; Jacobson et al., 2011; McCrimmon et al., 2012; Viscogliosi et al., 2012; Cato et al., 2014).