Spinocerebellar ataxias (SCA) comprise a set of progressive degenerative diseases, still without available pharmacological treatment, that cause gait and balance disorders. Two recent clinical trials demonstrated that the use of transcranial direct current stimulation (tDCS) cerebellar spinal cord improved performance on tests of upper limb coordination, severity of ataxia and gait (2 weeks of stimulation), and motor scores (including balance), cognitive and quality of life scores (4 non-consecutive weeks) in subjects with degenerative ataxias, including ACS.

The primary aim of this study is to evaluate how many sessions of cerebellar spinal tDCS associated with a gait training protocol a sample of individuals with ACS should receive until they stop showing improvements in the time, they can remain standing on one limb bottom. The impact of this intervention on measures of balance and gait performance will also be evaluated.

This is a pragmatic clinical trial protocol, in which 20 patients with different types of ACS will receive tDCS sessions associated with a gait training protocol with progressively greater difficulty. The tDCS will be applied for 20 min and intensity of 2mA, with the anode electrode positioned on the cerebellar region and the cathode on the thoracic region of the medulla (approximately T8). At each session, the time individuals manage to remain in unipodal support will be computed (less than three attempts). When the time in unipodal support is like that of age- and sex-matched healthy individuals, the protocol will be discontinued. Patients will also be evaluated before and after the end of the intervention using the Scale for the Assessment and Rating of Ataxia (SARA), dynamDynamic Gait Index (DGI), Minibest.

It is expected that multiple sessions of cerebellar-spinal tDCS associated with gait training promote an increase in the time that each participant is able to remain standing on one leg independently, resulting in a more stable gait and better balance.

The study is under development. The project will be defended this semester and after approval by the institution's research ethics committee, the volunteer recruitment phase will begin.

This study will help physiotherapists who use tDCS in patients with SCA3 in choosing the number of sessions that should be used to obtain satisfactory results regarding balance and gait in this population.