A promising new approach,
transcranial direct current stimulation (
tDCS) has recently been used as a therapeutic modality for
cerebellar ataxia. However, the strength of the conclusions drawn from individual studies in the current literature may be constrained by the small sample size of each trial. Following a systematic literature retrieval of studies, meta-analyses were conducted by pooling the standardized mean differences (SMDs) using random-effects models to assess the efficacy of
tDCS on
cerebellar ataxia, measured by standard clinical rating scales. Domain-specific effects of
tDCS on gait and hand function were further evaluated based on 8-m walk and 9-hole peg test performance times, respectively. To determine the safety of
tDCS, the incidences of adverse effects were analyzed using risk differences. Out of 293 citations, 5 randomized controlled trials involving a total of 72 participants with
cerebellar ataxia were included. Meta-analysis indicated a 26.1% (p = 0.003) improvement in
ataxia immediately after
tDCS with sustained efficacy over months (28.2% improvement after 3 months, p = 0.04) when compared with
sham stimulation.
tDCS seems to be domain-specific as the current analysis suggested a positive effect on gait (16.3% improvement, p = 0.04) and failed to reveal differences for hand function (p = 0.10) with respect to
sham. The incidence of adverse events in
tDCS and
sham groups was similar.
tDCS is an effective intervention for mitigating
ataxia symptoms with lasting results that can be sustained for months. This treatment shows preferential effects on
gait ataxia and is relatively safe.