These promising results provide an impetus for longer-term trial

Results suggest that the administration of intranasal insulin may have a therapeutic benefit for adults with aMCI or AD. Compared with the participants in the placebo group, participants treated with the 20-IU dose of insulin showed improved delayed memory, and both insulin doses (ie, 20 and 40 IU) preserved the study partner–rated ability to perform daily functions. General cognitive abilities, as assessed with the ADAS-cog, were also preserved by both doses of intranasal insulin. In exploratory analyses, changes in CSF Aβ42 levels and tau protein–to–Aβ42 ratios were associated with cognitive and functional changes for insulin-treated participants. Placebo-assigned participants showed decreased CMRGlc values in several brain regions, including the frontal, temporal, and parietal cortices as well as the precuneus and/or cuneus regions during the 4-month period, whereas insulin-treated participants showed no significant decline. Finally, no treatment-related severe adverse events occurred. These promising results provide an impetus for longer-term trials of intranasal insulin therapy in adults with aMCI or AD.