Anodal cerebellar tDCS does not alter beta oscillations or corticokinematic coherence in Friedreich's ataxia and healthy participants.

OBJECTIVE

To evaluate the effect of anodal cerebellar transcranial Direct Current Stimulation (ctDCS) on the excitability of the sensorimotor cortex (SM1), in Friedreich's ataxia (FA) and healthy participants.

METHODS

Nineteen FA and 17 healthy participants underwent a 10-day non-sham controlled anodal ctDCS intervention. SM1 excitability pre and post ctDCS was quantified with Magnetoencephalography-assessed resting beta amplitude and power, beta burst rate and duration, and the aperiodic component of oscillatory power. Cortical processing of proprioception pre and post ctDCS was assessed with Corticokinematic Coherence (CKC). FA patients' motor symptoms pre and post ctDCS were assessed with the Scale for the Assessment and Rating of Ataxia (SARA).

RESULTS

The resting beta amplitude, power, burst rate and duration, and the aperiodic component of oscillatory power did not differ significantly between FA and healthy participants. In both groups, these measures were not significantly affected by the anodal ctDCS. CKC was significantly lower in FA compared to healthy participants, however, it was not significantly affected by the ctDCS. In the FA group, a significant improvement in SARA score was found post ctDCS.

CONCLUSIONS

Anodal ctDCS improved FA motor symptom severity without altering SM1 excitability.

SIGNIFICANCE: Anodal ctDCS has a therapeutic effect in FA, however, the neurophysiology of this effect is complex and requires further investigation.