Supplementary role of once a week transcranial direct current stimulation session on visual processing rehabilitation after brain tumor: could it be unexpected additional benefit case study

Background and Aim : Around 28% of patients with a brain tumor report a problem with their vision (visual impairment). This could be a direct result of the tumor, or its treatments and resection. Severity of deficit is depending on the location and treatment of the brain tumor. Brain tumor resection side effects can include blurred or double vision, abnormal eye movements, restricted field of view and rarely complete loss of vision. The aim of this study is to report a single case who’s blindness as side effect of tumor surgery is recovering by slow and step by step with our visual –neuro psychological rehabilitation along with single session per week of transcranial direct current stimulation (tDCS).Methods : A 41-year-old male with resection of brain tumor on bifrontal area, three years ago, suffering from Complete loss of right eye vision, the sight of left eye is to the extend of shadow, and Complete loss of sense of smell. The intervention contains single session anodal tDCS (2 mA, 30 min) in occipital area combined with visual rehabilitation was implemented one times per week, 1 hours each, for 16 weeks (the study is on going)with every day 3 hours training program for home. In order to assess visual improvement function before and during the intervention, due to the extent of the impaired and low vision, the only method of measuring progress was retinal and perimeter examination which was conducted, and the family s report of a gradual improvement of patient’s daily living complemented our information.Results : Delivery of combined tDCS with visual perception training was feasible and safe. High-resolution perimeter revealed an admissible shift in visual field. Patient also showed effective recovery of function in activities of daily living. He was able to identify colors that he did not recognize at all after surgery in the main three colors means blue yellow and green. In addition, he is able to read letters, Single digit numbers and math symbols written in large font (45 font) from 40 cm distance monitor or paper.Conclusion : Results of this intervention suggest that occipital cortical tDCS may enhance recovery of visual function associated with concurrent visual perception rehabilitation even if the location of damage is in anterior visual pathways. Also, if the occipital area is modulated in conditions that are not directly impaired, the anterior pathway of visual system of the brain will benefit from this reinforcement. In fact, because of the networked nature of the visual pathways, this property can be used tDCS that means indirect stimulation of visual system can help far location of damage. This single-case study demonstrates for the first time that combined application of tDCS (as shadow treatment method) and restorative training may enhance improvements in measures of visual perception. Future studies, need to find how much could be efficient single session tDCS per week as adjuvant therapy compared to other protocol.

کلیدواژه ها:

one a week tDCs session ، vision neurppsycholigy rehabilitation ، vision restoration ، transcranial direct current stimulation