This study is a multicenter, randomized, double-blind, parallel-group, prospective confirmatory clinical trial designed to evaluate whether the Neuclare medical device can temporarily improve executive function (planning and problem-solving abilities) in adults with mild cognitive impairment or very early Alzheimer's disease. Participants will continue their current medication and be randomly assigned to receive either the Neuclare device (treatment group) or a sham device (control group). The device will be applied to the brain three times per week for four weeks. Both participants and study staff are blinded to the group assignment. Safety and adverse events will be closely monitored throughout the study. During the trial, assessments will include attention, cognitive function, daily living activities, brain imaging (Amyloid PET-CT), blood biomarkers, and quality of life (EQ-5D-5L). The goal of this study is to determine whether the Neuclare device, in combination with standard medication, can safely provide temporary improvements in executive function.