Marshall Randolph S, Ferrera John J, Barnes Anna, O'Brien Katherine A, Chmayssani Mohamad, Hirsch Joy, Lazar Ronald M
Department of Neurology Columbia University Medical Center, NY, NY 10032, USA.
Neurorehabil Neural Repair. 2008 Mar-Apr;22(2):136-44. doi: 10.1177/1545968307305522. Epub 2007 Aug 14.
Visual restoration therapy is a home-based treatment program intended to expand visual fields of hemianopic patients through repetitive stimulation of the borderzone adjacent to the blind field. We hypothesized that the training itself would induce visual field location-specific changes in the brain's response to stimuli, a phenomenon demonstrated in animal experiments but never in humans with brain injury.
Six chronic right hemianopic patients underwent functional magnetic resonance imaging (fMRI)--responding to stimuli in the trained visual borderzone versus the nontrained seeing field before and after 1 month of visual restoration therapy. Spatially normalized fMRI time-series data were analyzed in a fixed-effects group analysis comparing blood oxygen level dependent (BOLD) activity in the borderzone versus seeing location at baseline and at 1 month. Percent BOLD change was measured to determine each condition's contribution to the time-by-condition interaction.
There was a significant time by condition interaction manifested as increased BOLD activity for borderzone detection relative to seeing detection after the first month of therapy, which correlated with a relative improvement in response times in the borderzone location out-of-scanner. The right inferior and lateral temporal, right dorsolateral frontal, bilateral anterior cingulate, and bilateral basal ganglia showed the greatest response.
Visual restoration therapy appears to induce an alteration in brain activity associated with a shift of attention from the nontrained seeing field to the trained borderzone. The effect appears to be mediated by the anterior cingulate and dorsolateral frontal cortex in conjunction with other higher order visual areas in the occipitotemporal and middle temporal regions. Demonstration of a visual field-specific training effect on brain activity provides an important starting point for understanding the potential for visual therapy in hemianopia.
视觉恢复疗法是一种居家治疗方案，旨在通过对盲视野相邻的边界区进行重复刺激来扩大偏盲患者的视野。我们假设该训练本身会在大脑对刺激的反应中引发视野位置特异性变化，这种现象在动物实验中已得到证实，但在脑损伤患者中从未被证实过。
6名慢性右侧偏盲患者在接受1个月视觉恢复治疗前后，接受了功能磁共振成像（fMRI）检查，分别对训练后的视觉边界区和未训练的可见视野中的刺激做出反应。在固定效应组分析中，对空间归一化的fMRI时间序列数据进行分析，比较边界区与基线及1个月时可见位置的血氧水平依赖（BOLD）活动。测量BOLD变化百分比以确定每种条件对时间-条件交互作用的贡献。
存在显著的时间-条件交互作用，表现为治疗第一个月后，相对于可见检测，边界区检测的BOLD活动增加，这与边界区位置在扫描仪外的反应时间相对改善相关。右侧颞下和外侧、右侧背外侧额叶、双侧前扣带回和双侧基底神经节显示出最大反应。
视觉恢复疗法似乎会引起大脑活动的改变，这种改变与注意力从未训练的可见视野转移到训练后的边界区有关。这种效应似乎由前扣带回和背外侧额叶皮层与枕颞和颞中区域的其他高级视觉区域共同介导。证明视野特异性训练对大脑活动的影响为理解偏盲视觉治疗的潜力提供了一个重要的起点。
