Amnestic Mild Cognitive Disorder

This study will probe if the biological changes in amnestic mild cognitive impairment (aMCI) are related to a history of mild traumatic brain injury (mTBI) using high definition transcranial direct current stimulation (HD-tDCS) and blood-derived biomarker tools. Participants who Do as well as those who Do Not have a history of mTBI will be enrolled in the study.

This is a neuroimaging study designed to learn more about amyloid and tau burden in the brain of patients with typical and atypical Alzheimer's Disease and how burden may change over a one year period.

This clinical study aims to examine the effectiveness of a 12-week modified ketogenic diet (MKD) intervention, especially on cognitive functions, in individuals diagnosed with amnestic-mild cognitive impairment (aMCI) and to compare the effects of control groups (passive or active). Accordingly, a sample of 36 older adults aged 65-80 years diagnosed with aMCI will be randomized into 3 different groups: passive control (without any intervention), active control (MIND: Mediterranean-DASH Intervention for Neurodegenerative Delay diet) or intervention (MKD). They will be monitored according to targeted criteria throughout the 12-week study protocol. The main questions this study aims to answer are: * Does a 12-week MKD intervention improve cognitive functions in aMCI? * Does the effectiveness of the 12-week MKD intervention in aMCI (i.e., in terms of cognitive function, physical and functional measures, or metabolic/inflammatory biomarkers) differ from control groups? Expected from participants during the study protocol: * Participants assigned to the passive control arm are expected to come to the research center at the beginning (week 0) and end (week 12) of the protocol and participate in evaluations. * Participants assigned to the active control (MIND diet) or intervention (MKD) arm are expected to adhere to assigned dietary therapy, keep a weekly food diary, and have weekly phone calls or online meetings with the dietitian to follow up on the diet. These participants assigned to the diet groups are expected to come to the research center at weeks 0, 4, 8, and 12 to participate in the evaluations.