Sporadic and hereditary neurodegenerative ataxias are disabling diseases associated with tremors, dysarthria, and cognitive decline, with no effective treatments. Cerebral tDCS have shown improvements in the posture, gait, and kinetic functions in patients with ataxia. In addition to cerebral tDCS, spinal tDCS targeting neurodegeneration of spinal cord structures have also shown promising results in patients with spinal cord injuries. Because ataxia can cause degeneration in both cerebral and spinal cord, stimulation of both structures may help more than 1 stimulation alone. The purpose of the CStDCSAtaxia trial is to evaluate cerebello-spinal tDCS and its long-term effects in patients with neurodegenerative ataxia.

Patients with neurodegenerative ataxia that are treated with cerebello-spinal transcranial direct current simulation (tDCS) have significant improvements in gait, upper limb coordination, quality of life, and other neurological evaluations of cerebellar deficits, according to results from the CStDCSAtaxia trial.

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Patients with neurodegenerative ataxia received either concurrent stimulation of anodal cerebellar tDCS and cathodal spinal tDCS or sham stimulation for 2 weeks and were monitored for 3 months. Following an additional washout period of 3 months, each patient received the opposite treatment and underwent the same assessment as before. Improvements in ataxia were assessed through 2 clinical scales:

Scale for the Assessment and Rating of Ataxia (SARA)

International Cooperative Ataxia Rating Scale (ICARS)

Upper limb coordination was gauged through the 9-Hole Peg Test (9HPT), a test to check finger dexterity, while gait speed was evaluated through the 8-m walking time. A Short-Form Health Survey 36 (SF-36) was used to access quality of life.

SARA scores revealed a significant difference between treatment with tDCS versus sham stimulation at 2 weeks, 1 month, and 3 months (P < .001), but not at baseline (P = .422). ICARS scores also showed significant differences at 2 weeks, 1 month, and 3 months (P < .001), but not at baseline (P = .613). Individual assessment of the ICARS scale reviewed statistically significant differences in the posture/gait (P = .011) and limb coordination (P < .001), but not statistically significant for dysarthria (P =.235) or oculomotor movement (P = 1).

9HPT revealed a significant difference between tDCS treatment and sham stimulation in both the dominant and nondominant hand at 2 weeks, 1 month, and 3 months (P < .001) but not at baseline (dominant P = .670; nondominant P = .926). A significant improvement found in the 8-minute walking time was correspondingly seen at each endpoint (P < .05), and not for baseline (P = .414). A significant improvement in SF-36 scores (P < .05) at all endpoints except for baseline (P = .775) was seen in the tDCS treatment group, but not the sham stimulation group. Finally, cerebellar brain inhibition revealed significant increases in average resting motor cortex thresholds in the tDCS treatment group at all endpoints except for baseline, and none in the sham stimulation group.

Current pharmacologic and nonpharmacologic therapies for neurodegenerative ataxia are limited, with many patients having debilitating clinical symptoms. Treatment with cerebello-spinal tDCS seems to have a significant effect in helping patients with neurodegenerative ataxia and could be viewed as a potential line of treatment for rehabilitation.

Reference

Benussi A, Dell’Era V, Cantoni V, et al. Cerebello-spinal tDCS in ataxia a randomized, double-blind, sham-controlled, crossover trial. Neurology. 2018;91:1-12. doi:10.1212/WNL.0000000000006210.