The purpose of this project is to evaluate feasibility and preliminary efficacy of pairing personalized transcranial direct current stimulation (tDCS) with individualized rehabilitation therapy in people with cerebellar damage.

Cerebellar damage causes debilitating ataxia affecting balance, coordination, speech, and cognition. Rehabilitation therapy is the main treatment for ataxia because pharmacological therapeutics are extremely limited. Non-invasive brain stimulation has shown promise in improving motor function and has an excellent safety profile. However, optimal stimulation sites and efficacy when combined with rehabilitation remain unclear.

We hypothesize that three weeks of intensive rehabilitation therapy paired with personalized transcranial direct current stimulation (tDCS) will produce greater functional improvements in people with cerebellar damage compared to therapy with sham stimulation.

This double-blind, randomized, sham-controlled trial will enroll participants with cerebellar damage. We will determine stimulation sites using multimodal neuroimaging and electric field modeling and then check their response to stimulation. If they show MRI response to stimulation and it is well-tolerated, they will be eligible to receive 30 hours of training (one hour, twice daily), with active or sham tDCS during one of the daily sessions Primary outcomes are the Scale for Assessment and Rating of Cerebellar Ataxia (SARA) and Patient-Reported Outcome Measure of Ataxia (PROM-Ataxia), assessed pre-treatment, post-treatment, and at 3- and 6-month follow-ups.

This research addresses a critical gap in treatment options for cerebellar ataxia by testing whether personalized neuromodulation enhances rehabilitation outcomes.

Inclusion Criteria:

• Age 18-75 years
• Males and Females
• Disorders that predominantly affect the cerebellum: damage from stroke, tumor or degeneration (genetic or non-genetic causes, congenital hypoplasia).

Exclusion Criteria:

• Diagnoses or impairments that interfere with task execution or data interpretation.
• Heart pacemaker or other MRI-incompatible implanted metal device
• Metallic foreign body in their eye or head
• Experience with severe claustrophobia
• Experience discomfort from the MRI scan, such as excessive heating of tattoos
• Seizures or history of seizure disorder
• Alcohol or substance use disorder (self-report)
• Diagnosed history of severe psychiatric disorder such as depression, schizophrenia (self-report)
• Metallic foreign body in their eye or head (except the mouth e.g. dental fillings)
• Specific medications: tricyclic anti-depressants or neuroleptic medication
• Any medical condition (including orthopedic, pain, cardiopulmonary or other) that limits safe participation in exercise training

Participants will be masked in regards to receiving active or sham tDCS.