Cerebellar Non-invasive Stimulation in Ataxias

Cerebellar ataxias are a group of disorders caused by cerebellar affections, for which currently no specific treatment is available. Some limited studies verified the effects of cerebellar transcranial magnetic stimulation (TMS) on ataxic symptoms, with good results. So far it is not known which patients could benefit. Our hypothesis is that cerebellar TMS could improve ataxic symptoms in some patients.

Thirty patients with cerebellar ataxia will be included in our protocol. Ataxia might be due to several aetiologies, from degenerative to genetic and vascular diseases. Patients will be submitted to a neuronavigation protocol for the precise location of the dentate nucleus contralateral to the most symptomatic side. After that, participants will be randomly assigned to 5 active or 5 placebo sessions of 1Hz TMS over the located area. After the first 5 sessions and a period of at least 4 weeks washout, patients will cross over and receive other 5 sessions, active or sham. Clinical and video evaluations will be conducted before and after active and sham cluster of sessions.

Low frequency (1Hz) transcranial magnetic stimulation aimed to the dentate nucleus contralateral to the most symptomatic side.

The stimulation coil will be placed in the same spot as the TMS stimulation, but coil will not be attached to the TMS machine.

Percent Change From Baseline to Post Treatment on the Scale for the Assessment and Rating of Ataxia (SARA)

Assess 8 items: gait, stance, sitting, speech, dysmetria, kinetic tremor, pro- and supinations of the hand, and the heel-shin slide. Each item is scored by the physician on a 4 to 8 numerical scale based upon the amount of dysfunction observed while performing the task. The maximum possible score for the total scale is 40. Lower scores of SARA represents better task performance.

Day 1 (baseline), day 5 (after 5th TMS session, active or sham), day 33 (new baseline after TMS wash out) and day 38 (after 10th TMS session, active or sham)

Inclusion Criteria: identification of cerebellar ataxia based on neurologic examination no improvement after rehabilitation symptoms onset of at least 6 months Exclusion Criteria: Younger than 18 months Pregnant or breastfeeding women Participation in other clinical trials Epilepsy

Franca C, de Andrade DC, Silva V, Galhardoni R, Barbosa ER, Teixeira MJ, Cury RG. Effects of cerebellar transcranial magnetic stimulation on ataxias: A randomized trial. Parkinsonism Relat Disord. 2020 Nov;80:1-6. doi: 10.1016/j.parkreldis.2020.09.001. Epub 2020 Sep 6.