Henriksson L, Raninen A, Näsänen R, Hyvärinen L, Vanni S
Advanced Magnetic Imaging Centre and Brain Research Unit of Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland.
J Neurol Neurosurg Psychiatry. 2007 Jan;78(1):74-81. doi: 10.1136/jnnp.2006.099374. Epub 2006 Sep 15.
Patients with homonymous hemianopia often have some residual sensitivity for visual stimuli in their blind hemifield. Previous imaging studies suggest an important role for extrastriate cortical areas in such residual vision, but results of training to improve vision in patients with hemianopia are conflicting.
To show that intensive training with flicker stimulation in the chronic stage of stroke can reorganise visual cortices of an adult patient.
A 61-year-old patient with homonymous hemianopia was trained with flicker stimulation, starting 22 months after stroke. Changes in functioning during training were documented with magnetoencephalography, and the cortical organisation after training was examined with functional magnetic resonance imaging (fMRI).
Both imaging methods showed that, after training, visual information from both hemifields was processed mainly in the intact hemisphere. The fMRI mapping results showed the representations of both the blind and the normal hemifield in the same set of cortical areas in the intact hemisphere, more specifically in the visual motion-sensitive area V5, in a region around the superior temporal sulcus and in retinotopic visual areas V1 (primary visual cortex), V2, V3 and V3a.
Intensive training of a blind hemifield can induce cortical reorganisation in an adult patient, and this case shows an ipsilateral representation of the trained visual hemifield in several cortical areas, including the primary visual cortex.
同向性偏盲患者在其盲半视野中对视觉刺激通常仍有一定残余敏感性。先前的影像学研究表明，纹外皮质区域在这种残余视力中起重要作用，但改善偏盲患者视力的训练结果存在矛盾。
证明在卒中慢性期进行闪烁刺激强化训练可使成年患者的视觉皮质重新组织。
一名61岁的同向性偏盲患者在卒中22个月后开始接受闪烁刺激训练。训练期间的功能变化通过脑磁图记录，训练后的皮质组织通过功能磁共振成像（fMRI）检查。
两种成像方法均显示，训练后，来自两个半视野的视觉信息主要在完整半球中处理。fMRI映射结果显示，在完整半球的同一组皮质区域，更具体地说是在视觉运动敏感区域V5、颞上沟周围区域以及视网膜拓扑视觉区域V1（初级视觉皮质）、V2、V3和V3a中，盲半视野和正常半视野均有表征。
对盲半视野进行强化训练可在成年患者中诱导皮质重组，该病例显示在包括初级视觉皮质在内的几个皮质区域中，训练后的视觉半视野有同侧表征。
