Efficacy of tDCS in Degenerative Ataxia

Efficacy of Cerebellar Transcranial Direct Current Stimulation in Degenerative Ataxia. A Sham-controlled Clinical and Quantitative Analysis.

Degenerative cerebellar ataxias are a group of rare diseases that cause gradual damage to the cerebellum, the part of the brain that controls balance and coordination. People with these conditions may have difficulty walking, keeping their balance, or coordinating movements. They may also experience vision problems, muscle stiffness, tremors, or changes in behavior, depending on the specific cause of the disease.

These disorders can greatly affect independence and quality of life, and unfortunately, there are currently no treatments that can stop or reverse the disease. Most care focuses on managing symptoms with physical therapy and medication.

Recently, a non-invasive brain stimulation technique called transcranial direct current stimulation (tDCS) has been studied as a possible way to improve movement and thinking in people with ataxia. However, results so far have been mixed, possibly because of differences in disease type, treatment methods, and how improvements are measured.

New technologies, such as motion sensors and movement analysis, are helping researchers better measure the effects of treatments on walking, balance, and hand movements in daily life.

The goal of the current study is to test whether stimulating the cerebellum with anodal tDCS can improve movement in people with different types of degenerative ataxia. The study will use both standard clinical scales and precise movement analysis to measure changes. In addition, researchers will use brain recordings (EEG) taken before and after stimulation to better understand how tDCS may work in the brain

Study Overview

• Status: Active, not recruiting
• Conditions: Ataxia, Spinocerebellar; Ataxia, Cerebellar; Ataxia - Genetic Diagnosis - Unknown; Ataxias, Hereditary
• Intervention / Treatment: Device: Sham (No Treatment); Device: transcranial direct current stimulation

Detailed Description

Degenerative cerebellar ataxias are a heterogeneous group of inherited and acquired disorders characterized by cerebellar atrophy and degeneration which leads to a wide range of clinical symptoms. Indeed, beside cerebellar symptoms such as gait ataxia, postural unbalance, dysmetria and nystagmus, patients may exhibit peripheral neuropathy, pyramidal and extrapyramidal signs and behavioural symptoms, depending on the aetiology of the disorder.

These disorders substantially affect autonomy and quality of life, yet effective disease-modifying or symptomatic treatments remain limited; their current management is largely supportive, including physical therapy and symptomatic pharmacological interventions.

Among non-pharmacological treatments, cerebellar transcranial direct current stimulation (tDCS), a non-invasive brain stimulation (NIBS) technique, has been employed in several studies with the aim to improve both motor and cognitive symptoms in different forms of ataxia, with conflicting results, so that, at present, it is not possible to determine its therapeutic potential with certainty. In this regard, it has been hypothesized that the large variability of clinical outcomes associated with such approach is due to several factors including, among the most relevant, the heterogeneity of ataxia aetiology, the significant differences in terms of protocols of stimulation and the lack of sensitive objective measures to be integrated with the scales traditionally employed in the clinical routine. Indeed, in the last years, quantitative analysis of movement (performed using either motion capture system or wearable inertial sensors) has shown to be a reliable approach to assess, in combination with clinical data, the existence and magnitude of possible positive effects induced by NIBS on basic motor functions (i.e., gait and balance) as well as to monitor real-world mobility and characterize physical activity patterns of people with ataxia.

The ability of cerebellar tDCS to influence the cerebellar-thalamus-cortical pathway has been demonstrated by the cerebellar-brain inhibition (CBI) TMS paradigm. Moreover, the cerebellar-cortical connectivity has been explored with NIBS combined with functional magnetic resonance imaging (fMRI) and EEG with online and offline paradigms. Several studies show that cerebellar NIBS is able to influence cortical oscillations and that an increase of beta power in frontal and parietal region is involved sensory-motor integration and motor control through the modulation of the cerebellar-thalums cortical circuit; the role of cortical gamma oscillation on motor activity following cerebellar stimulation is less characterized, but some evidence indicates that cortical gamma activity reflects excitatory action of the cerebellum on the motor thalamus and the motor cortex. However, in this case the results are controversial probably due to the heterogeneous methodological approaches.

Based on these observations, the aim of the present study was to assess the efficacy of cerebellar anodal tDCS in improving ataxia in different forms of degenerative ataxia with a sham-controlled approach, using validated clinical rating scales as well as quantitative techniques for human movement analysis focused on gait and upper limb functionality (i.e., hand-to-mouth task) as data on these motor tasks are already available for people with ataxia.

Moreover, in order to explore the mechanism underlying the therapeutic effect of cerebellar tDCS data obtained from resting state EEG before and after stimulation will be analyzed.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Cagliari, Italy, 09100
    • University of Cagliari

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• clinical, radiological and/or genetic diagnosis of cerebellar ataxia

Exclusion Criteria:

• presence of electrical stimulators (i.e., pacemaker), pregnancy, visual disfunction, cognitive decline, mild to moderate ataxic symptoms

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Sham Comparator: Sham; For sham stimulation the tDCS device delivered just a short ramp of current to let patients feel a skin sensation similar to those perceived by those actually treated.	Device: Sham (No Treatment); In the "Sham" arm, no current was delivered to the brain except for the initial few seconds; Other Names: Sham
Active Comparator: Real	Device: transcranial direct current stimulation; Anodal stimulation is delivered by a battery-driven stimulator (NeuroConn GmbH, 98693 Ilmenau, Germany) through a pair of saline-soaked surface sponge electrodes (7 x 5 cm2) producing a constant current of 2 mA for 20 min. An electroconductive gel is applied to the electrodes to reduce contact impedance and the electrodes are held in place using elastic gauzes Stimulation is preceded by a ramping up and ramping down for 20 sec at the beginning and at the end of each session, respectively. The anode is placed 2 cm under the inion and the cathode was placed over the right deltoid muscle. For sham stimulation the machine did not deliver any current after the ramping up, so both groups of patients could feel the same skin sensation.; Other Names: Real

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Modified International Cooperative Ataxia Rating Scale (MICARS)	The Modified International Cooperative Ataxia Rating Scale (MICARS) is a clinical tool used to assess and quantify the severity of ataxia, a neurological condition characterized by impaired coordination and balance. It is a streamlined version of the original International Cooperative Ataxia Rating Scale (ICARS), designed to improve ease of use, reliability, and sensitivity to clinical changes. MICARS evaluates key domains such as gait and posture, limb coordination, speech, and eye movements, providing a numerical score that reflects overall ataxia severity. It is commonly used in both clinical practice and research to monitor disease progression and treatment effects in patients with cerebellar ataxia and related disorders.	Before the first tDCS session (T0) and after 10 sessions (2 weeks)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Scale for the Assessment and Rating of Ataxia (SARA)	The Scale for the Assessment and Rating of Ataxia (SARA) is a standardized clinical tool used to evaluate the severity and progression of ataxia. It consists of eight performance-based items that assess functions such as gait, stance, sitting, speech, and limb coordination (including finger-chase, nose-finger test, fast alternating hand movements, and heel-shin slide). Each item is scored on a defined scale, and the total score ranges from 0 (no ataxia) to 40 (most severe ataxia). SARA is valued for its simplicity, reliability, and sensitivity to change, making it widely used in both clinical trials and routine neurological assessments of cerebellar disorders.	Before the first tDCS session (T0) and after 2 weeks (10 sessions)
Robertson Dysarthria profile	The Robertson Dysarthria Profile is a comprehensive clinical assessment tool used to evaluate and document speech difficulties associated with dysarthria, a motor speech disorder caused by neurological impairment. It examines key aspects of speech production, including respiration, phonation, articulation, resonance, and prosody, as well as the patient's intelligibility and communication effectiveness. The profile helps clinicians identify the type and severity of dysarthria, monitor changes over time, and plan targeted therapy. It is particularly useful in both diagnostic assessment and treatment planning for individuals with acquired or developmental speech motor disorders.	Befofe the first tDCS session and after 2 weeks (10 sessions)

Collaborators and Investigators

• Sponsor: University of Cagliari

Study record dates

Study Major Dates

• Study Start (Actual): October 9, 2023
• Primary Completion (Actual): July 21, 2025
• Study Completion (Estimated): December 1, 2025

Study Registration Dates

• First Submitted: November 18, 2025
• First Submitted That Met QC Criteria: November 18, 2025
• First Posted (Actual): November 26, 2025

Study Record Updates

• Last Update Posted (Actual): November 26, 2025
• Last Update Submitted That Met QC Criteria: November 18, 2025
• Last Verified: November 1, 2025

More Information

Terms related to this study

• Keywords: tDCS; gait; upper limb; non-invasive brain stimulation; ataxia; quantitative analysis
• Additional Relevant MeSH Terms: Neurologic Manifestations; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Genetic Diseases, Inborn; Neurodegenerative Diseases; Heredodegenerative Disorders, Nervous System; Spinal Cord Diseases; Dyskinesias; Cerebellar Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Ataxia; Cerebellar Ataxia; Spinocerebellar Ataxias; Spinocerebellar Degenerations; Therapeutics; Behavioral Disciplines and Activities; Electric Stimulation Therapy; Convulsive Therapy; Psychiatric Somatic Therapies; Electroshock; Psychological Techniques; Transcranial Direct Current Stimulation
• Other Study ID Numbers: 4642022/CE Study Code tDCS-ATX

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Individual Participant Data (IPD) that will be collected throughout the trial will include all de-identified data relevant to the study's primary and secondary outcomes as well as demographic and clinical characteristics
• IPD Sharing Time Frame: From January 2026 to December 2026
• IPD Sharing Access Criteria: Researcher and clinicians involved in ataxia studies
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; ICF; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No