Transcranial Direct Current Stimulation Enhances Recovery of Stereopsis in Adults With Amblyopia
- 682 Downloads
Amblyopia is a neurodevelopmental disorder of vision caused by abnormal visual experience during early childhood that is often considered to be untreatable in adulthood. Recently, it has been shown that a novel dichoptic videogame-based treatment for amblyopia can improve visual function in adult patients, at least in part, by reducing inhibition of inputs from the amblyopic eye to the visual cortex. Non-invasive anodal transcranial direct current stimulation has been shown to reduce the activity of inhibitory cortical interneurons when applied to the primary motor or visual cortex. In this double-blind, sham-controlled cross-over study we tested the hypothesis that anodal transcranial direct current stimulation of the visual cortex would enhance the therapeutic effects of dichoptic videogame-based treatment. A homogeneous group of 16 young adults (mean age 22.1 ± 1.1 years) with amblyopia were studied to compare the effect of dichoptic treatment alone and dichoptic treatment combined with visual cortex direct current stimulation on measures of binocular (stereopsis) and monocular (visual acuity) visual function. The combined treatment led to greater improvements in stereoacuity than dichoptic treatment alone, indicating that direct current stimulation of the visual cortex boosts the efficacy of dichoptic videogame-based treatment. This intervention warrants further evaluation as a novel therapeutic approach for adults with amblyopia.
KeywordsAmblyopia Plasticity tDCS Stereopsis Inhibition
This work was supported by a Faculty of Science Research Development Fund and Early Career Research Excellence Award, University of Auckland; an Auckland Medical Research Foundation Project Grant; and a Health Research Council Grant to BT; a National Natural Science Foundation of China Grant (81200715); a Thrasher Research Fund for Early Career Award to JL; and a Canadian Institutes of Health Research Grant (53346) to RFH. We thank Dr Long To and Dr Jeremy Cooperstock for their collaboration, and Dr Avinesh Pillai for valuable assistance with the statistical analysis.
Required Author Forms
Disclosure forms provided by the authors are available with the online version of this article.
- 9.Wallace DK, Lazar EL, Melia M, et al. Stereoacuity in children with anisometropic amblyopia. JAAPOS 2011;15:455–461.Google Scholar
- 15.Maya-Vetencourt JF, Baroncelli L, Viegi A, et al. IGF-1 restores visual cortex plasticity in adult life by reducing local GABA levels. Neural Plas 2012;250421.Google Scholar
- 23.To L, Thompson B, Blum J, Hess R, Maehara G, Cooperstock J. A game platform for treatment of amblyopia. IEEE Trans Neural Syst Rehabil Eng 2011;PP:1–1.Google Scholar
- 26.Spiegel DP, Byblow WD, Hess RF, Thompson B. Anodal transcranial direct current stimulation transiently improves contrast sensitivity and normalises visual cortex activation in individuals with amblyopia. Neurorehab Neural Repair 2013 Jun 17 [Epub ahead of print].Google Scholar
- 32.Clavagnier S, Thompson B, Hess RF. Long lasting effects of daily theta burst rTMS sessions in the human amblyopic cortex. Brain Stimul 2013 Apr 28 [Epub ahead of print].Google Scholar
- 51.Chatrian GE, Lettich E, Nelson PL. Ten percent electrode system for topographic studies of spontaneous and evoked EEG activities. Am J EEG Technol 1985;25:83–92.Google Scholar
- 62.Baroncelli L, Braschi C, Spolidoro M, Begenisic T, Maffei L, Sale A. Brain plasticity and disease: a matter of inhibition. Neural Plas 2011;286073.Google Scholar