Long term at-home treatment with transcranial direct current stimulation (tDCS) improves symptoms of cerebellar ataxia: a case report

Abstract

Background: Progressive cerebellar ataxia is a neurodegenerative disorder without effective treatment options that seriously hinders quality of life. Previously, transcranial direct current stimulation (tDCS) has been demonstrated to benefit cerebellar functions (including improved motor control, learning and emotional processing) in healthy individuals and patients with neurological disorders. While tDCS is an emerging therapy, multiple daily sessions are needed for optimal clinical benefit. This case study tests the symptomatic benefit of remotely supervised tDCS (RS-tDCS) for a patient with cerebellar ataxia.

Methods: We report a case of a 71-year-old female patient with progressive cerebellar ataxia, who presented with unsteady gait and balance impairment, treated with tDCS. tDCS was administered using our RS-tDCS protocol and was completed daily in the patient's home (Monday - Friday) with the help of a trained study technician. tDCS was paired with 20 min of simultaneous cognitive training, followed by 20 min of physical exercises directed by a physical therapist. Stimulation consisted of 20 min of 2.5 mA direct current targeting the cerebellum via an anodal electrode and a cathodal electrode placed over the right shoulder. The patient completed baseline and treatment end visits with neurological, cognitive, and motor (Lafayette Grooved Pegboard Test, 25 ft walk test and Timed Up and Go Test) assessments.

Results: The patient successfully completed sixty tDCS sessions, 59 of which were administered remotely at the patient's home with the use of real time supervision as enabled by video conferencing. Mild improvement was observed in the patient's gait with a 7% improvement in walking speed, which she completed without a walking-aid at treatment end, which was in stark contrast to her baseline assessment. Improvements were also achieved in manual dexterity, with an increase in pegboard scores bilaterally compared to baseline.

Conclusions: Results from this case report suggest that consecutively administered tDCS treatments paired with cognitive and physical exercise hold promise for improving balance, gait, and manual dexterity in patients with progressive ataxia. Remotely supervised tDCS provides home access to enable the administration over an extended period. Further controlled study in a large group of those with cerebellar ataxia is needed to replicate these findings.

Trial registration: ClinicalTrials.gov Identifier: NCT03049969 . Registered 10 February 2017- Retrospectively registered.

Keywords: Cerebellar ataxia; Cerebellar tDCS; Remotely supervised tDCS; Telerehabilitation; Transcranial direct current stimulation (tDCS).

Fig. 1

Example of the RS-tDCS kit and the electrodes preparation and positioning: tDCS headstrap for electrode cerebellar montage with the anode aligned with the median line over the cerebellum and the cathode over the right shoulder; stimulation device; single-use pre-saturated electrodes; laptop. a and b showed the positioning of the headstrap and the checking of its correct placement by the study technician connected via video conferencing. c and d showed the positioning of the cathode over the right shoulder and the releasing of the code to unlock the stimulation device for starting the session

Fig. 2

Modelling of the electric field intensity of cerebellar electrode placement. Theoretical model of electric field distribution generates using anodal electrode on the medial line over the whole cerebellum and cathodal electrode on the right shoulder at 2.5 mA. The stimulation montage targeting the cerebellar region is tailored by generating the current flow using the HD-Explore software (Soterix Medical, NY, USA)

Fig. 3

3-D Model showing the electric field intensity distribution of cerebellar electrode placement. 3-D theoretical model of electric field distribution generates using anodal electrode over the cerebellum and cathodal electrode on the right shoulder at 2.5 mA. The current flow distribution is generated using the HD-Explore software (Soterix Medical, NY, USA)