Open AccessNon-invasive electrical brain stimulation for vision restoration after stroke: An exploratory randomized trial (REVIS)
Author(s) -
Silja Räty,
Carolin Borrmann,
Giuseppe Granata,
Lizbeth Cárdenas-Morales,
A. Schoenfeld,
Michael Sailer,
Katri Silvennoinen,
Juha M. Holopainen,
Francesca Rossi,
Andrea Antal,
Paolo Maria Rossini,
Turgut Tatlısumak,
Bernhard A. Sabel
Publication year - 2021
Publication title -
restorative neurology and neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.768
H-Index - 77
eISSN - 1878-3627
pISSN - 0922-6028
DOI - 10.3233/rnn-211198
Subject(s) - transcranial direct current stimulation , stroke (engine) , visual field , visual cortex , randomized controlled trial , brain stimulation , medicine , psychology , stimulation , physical medicine and rehabilitation , neuroscience , surgery , mechanical engineering , engineering
Background: Occipital strokes often cause permanent homonymous hemianopia leading to significant disability. In previous studies, non-invasive electrical brain stimulation (NIBS) has improved vision after optic nerve damage and in combination with training after stroke. Objective: We explored different NIBS modalities for rehabilitation of hemianopia after chronic stroke. Methods: In a randomized, double-blinded, sham-controlled, three-armed trial, altogether 56 patients with homonymous hemianopia were recruited. The three experiments were: i) repetitive transorbital alternating current stimulation (rtACS, n = 8) vs. rtACS with prior cathodal transcranial direct current stimulation over the intact visual cortex (tDCS/rtACS, n = 8) vs. sham (n = 8); ii) rtACS (n = 9) vs. sham (n = 9); and iii) tDCS of the visual cortex (n = 7) vs. sham (n = 7). Visual functions were evaluated before and after the intervention, and after eight weeks follow-up. The primary outcome was change in visual field assessed by high-resolution and standard perimetries. The individual modalities were compared within each experimental arm. Results: Primary outcomes in Experiments 1 and 2 were negative. Only significant between-group change was observed in Experiment 3, where tDCS increased visual field of the contralesional eye compared to sham. tDCS/rtACS improved dynamic vision, reading, and visual field of the contralesional eye, but was not superior to other groups. rtACS alone increased foveal sensitivity, but was otherwise ineffective. All trial-related procedures were tolerated well. Conclusions: This exploratory trial showed safety but no main effect of NIBS on vision restoration after stroke. However, tDCS and combined tDCS/rtACS induced improvements in visually guided performance that need to be confirmed in larger-sample trials. NCT01418820 (clinicaltrials.gov)