The researchers hope to find out effects of transcranial direct current stimulation (tDCS) sessions on the behavioral symptoms of Huntington's Disease. If participants are eligible to continue, they will be provided a device to administer the tDCS for 30 minutes each day and be asked to answer questions with the study staff . Participants will be asked to return to the study center for follow ups and to undergo additional cognitive tests and questionnaires. Participants will also be asked to answer questionnaires via a web conferencing platform (Zoom) during the course of the study. Caregivers of the participants will be asked to answer questionnaires to collect more information about the participants.

This clinical trial will investigate the effects of transcranial direct current stimulation (tDCS) over cognitive and behavioral symptoms of patients with Huntington's disease (HD). The study will also investigate underlying neurobiological mechanisms of tDCS in HD.

Inclusion Criteria:

1. individuals aged 18-85 years with confirmed HD mutation and/or established family history alongside typical symptoms (i.e., chorea) of HD;
2. early (stages 1 and 2) or moderate (stage 3) stages according to Shoulson-Fahn criteria, also known as the UHDRS total functional capacity (TFC) scale (Bates, Tabrizi, and Jones 2014);
3. exhibit mild to moderate behavioral symptoms defined by severity scores in the PBA-S between 1 and 3 for any of the evaluated symptoms and no symptoms with a severity score of 4;
4. stable doses of medications for at least one month.
5. Ability of subject to understand and the willingness to sign a written informed consent document.
6. Have a caregiver willing to be present during tDCS sessions and answer questionnaires.

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 as well as answer questions related to their health and care.

Exclusion Criteria:

1. Unstable medical conditions (e.g. unstable angina, uncontrolled diabetes and hypertension, advanced cancer, etc.);
2. History of epilepsy;
3. Clinical diagnosis of major cognitive disorder (i.e., dementia);
4. 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 (Posner et al. 2011);
5. Being an active participant in other therapeutic clinical trial;
6. Determined to be incapable of consent per PMH or via assessment by the study staff at time of consent.
7. Participant has a pacemaker or any other implanted device/material contraindicated in the use of tDCS per current labeling requirements.

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.