Participants will be asked to participate in this research study of a device that creates transcranial direct current stimulation (tDCS).

The researchers hope to learn if 30 minute sessions of transcranial direct current stimulation (tDCS) improve such a mood or feelings in people with Alzheimer's Disease.

This study involves the use of an investigational device called a tDC stimulator. "Investigational" means that the device has not yet been approved by the U.S. Food & Drug Administration (FDA) for treating Alzheimer's Disease.

This study will help find out what effects, good and/or bad, this has. The safety of this device in humans has been tested in prior research studies; however, some side effects may not yet be known.

Three in-person visits will occur: (1) on the week prior to the first day of stimulation visit patients will undergo brain MRI scan to collect T1, T2, DWI and resting state functional MRI (rs-fMRI), and functional Near-Infrared Spectroscopy/Electroencephalography (fNIRS/EEG) imaging. In this visit, patients and caregivers will be taught how to operate the tDCS device and will receive a unit to take home; (2) on the day after completing the first treatment period, patients will undergo a second MRI scan with the same sequences and fNIRS/EEG imaging; (3) on the day after completing the second treatment period, at the end of week 5, patients will return the tDCS device to the study team and perform a last fNIRS/EEG imaging.

At in-person visits and during treatment periods patients will be asked questions regarding tolerability and acceptability, including monitoring for side effects, as well as completing questionnaires that assess cognition and NPS. All sessions will be remotely supervised via video conference platform.

Inclusion Criteria:

1. Ability of subject to understand and the willingness to sign a written informed consent document.
2. Individuals who are 60 years or older.
3. Diagnosis of possible or probable AD according to the National Institute of Aging - Alzheimer's Association diagnostic criteria; individuals with mild cognitive impairment (MCI) due to AD, as defined by these criteria, are eligible if biomarker evidence supports the underlying AD pathology (e.g., amyloid or tau positivity in CSF or PET imaging).
4. In the determination of the PI in consultation with the delegated physician(s) patient's signs/symptoms are consistent with: a Clinical Dementia Rating (CDR) of 0.5 (MCI) with biomarker evidence of AD; or a Clinical Dementia Rating score of 1-2 (mild to moderate dementia).
5. Clinically meaningful AS of ADRD is defined by the presence of any affective symptom (i.e., depression, elation, anxiety, irritability, and apathy) and a total severity score on the NPI-Q ≥10.
6. Have an eligible caregiver willing to be present during stimulation sessions and answer questionnaires (see criteria below).
7. Can speak and read in English.
8. Stable doses of medications for at least one month.
9. Access to a reliable broadband internet connection.

Caregiver

1. An adult who serves as an unpaid caregiver for an individual enrolled in the study as interpreted by the PI or delegate physician.
2. Adequate cognitive capacity to provide verbal consent to participate in the caregiver arm of the study.
3. Adequate reading, writing, hearing and verbal capacity to provide collateral information about the study participant, answer questions related to their health and care, and assist in tDCS sessions,

Exclusion Criteria:

1. Unstable medical conditions (e.g. unstable angina, uncontrolled diabetes and hypertension, advanced cancer, etc.) that, in the opinion of the PI in consultation with delegated physician(s) would contraindicate study participation for safety or data quality reasons.
2. Medical history of serious psychiatric disorders (i.e. bipolar disorder, schizophrenia, manic depression etc.).
3. History of epilepsy.
4. Metallic objects in the brain, skull, or otherwise placed where it could interfere with DCS.
5. Have risk of suicidal behavior, defined as any suicidal behavior or suicidal ideation of type 4 (active suicidal ideation with some intent to act, without specific plan) or type 5 (active suicidal ideation with specific plan and intent) based on the Columbia-Suicide Severity Rating Scale (C-SSRS) in the 3 months prior to screening;
6. Unwillingness to undergo MRI at baseline and during the Week 2 conversion period for reasons other than a confirmed medical contraindication such as having a pacemaker or other implanted medal making MRI unsafe.
7. Being an active participant in other therapeutic clinical trial.

Caregiver

1. Any individual who does not meet all the inclusion criteria

Data collected for this study will be analyzed and stored at the Glenn Bigs Institute for Alzheimer's and Neurodegenerative diseases at UT Health San Antonio. After the study is completed, the de-identified, archived data will be transmitted to and stored at the Glenn Bigs Institute for Alzheimer's and Neurodegenerative diseases at UT Health San Antonio, for use by other researchers including those outside of the study. Permission to transmit data to the Glenn Biggs Institute for Alzheimer's and Neurodegenerative diseases at UT Health San Antonio will be included in the informed consent.

When the study is completed and data is analyzed.

Patients will be blinded throughout the trial. As the application of tDCS electrical current over the skin can be perceived by the participants, the study team will employ a sham condition that has been shown to be reliable and indistinguishable from active treatment in previous clinical trials published in the available scientific literature. An individual on the study team will be delegated to randomize and program and re-program devices. Participants will act as their own control. The researcher supervising the stimulation will be blinded to the intervention the participant is receiving.