Prefronto–cerebellar transcranial direct current stimulation improves visuospatial memory, executive functions, and neurological soft signs in patients with euthymic bipolar disorder

OBJECTIVE The aim of the study was to improve neuropsychological functioning of euthymic patients with bipolar disorder (BD) using transcranial direct current stimulation (tDCS) applied to cerebellar and prefrontal cortices. METHODS Twenty-five BD outpatients underwent prefrontal (anodal) and cerebellar (cathodal) tDCS for 3 consecutive weeks. All participants were assessed through the Rey Complex Figure Test delay and copy and the Neurological Examination Scale at baseline and after therapy with tDCS. RESULTS After tDCS treatment, patients showed significant improvements in visuospatial memory tasks. Patients with worse baseline cognitive performances also showed a significant improvement in executive functioning tasks. Neurological Examination Scale total score and motor coordination subscale significantly improved. CONCLUSION Prefrontal-excitatory and cerebellar-inhibitory stimulations in euthymic BD patients may lead to better neurocognitive performances. This improvement could result from the modulation of prefronto-thalamic-cerebellar circuit activity pattern, which can be disrupted in BD.