Nelles Gereon, Pscherer Anja, de Greiff Armin, Forsting Michael, Gerhard Horst, Esser Joachim, Diener H Christoph
Neurologische Klinik und Poliklinik, Universitätsklinikum Essen, Essen 45122, Germany.
J Neurol. 2009 May;256(5):726-33. doi: 10.1007/s00415-009-5005-x. Epub 2009 Feb 25.
Substantial disability in patients with hemianopia results from reduced visual perception. Previous studies have shown that these patients have impaired saccades. Improving exploratory eye movements with appropriate training of saccades may help to partially compensate for the visuoperceptive impairment during daily life activities. The changes in cortical control of eye movements that may be induced by these training strategies, however, are not known. We used functional magnetic resonance imaging (fMRI) to study the training effects of eye-movement training on cortical control of saccades. Brain activation during visually guided saccades was measured in eight patients with an occipital cortical lesion causing homonymous hemianopia. Starting 8 weeks after the stroke, patients received 4 weeks of visual field training. The fMRI measurements were performed at baseline and after training. In five patients, follow-up fMRI was performed 4 weeks after the end of training. Differences in activation between rest and saccades as well as before and after training were assessed with statistical parametric mapping software (SPM'99). Twelve healthy subjects were scanned twice at a 4-week interval. In patients, significant activation at baseline was found in the frontal and parietal eye fields (FEF and PEF, respectively) bilaterally and in the supplementary eye field (SEF). Immediately after training, an area of increased activation was found in the left extrastriate cortex of the affected hemisphere. At follow-up, relatively more activation was found in the right peristriate cortex and in the SEF of the unaffected side. A relative decrease of activation was found in the left FEF. In this group of patients, eye-movement training induced altered brain activation in the striate and extrastriate cortex as well as in oculomotor areas.
偏盲患者的严重残疾是由视觉感知降低所致。先前的研究表明，这些患者的扫视运动受损。通过适当的扫视训练来改善探索性眼球运动，可能有助于在日常生活活动中部分补偿视觉感知障碍。然而，这些训练策略可能诱发的眼球运动皮质控制的变化尚不清楚。我们使用功能磁共振成像（fMRI）来研究眼球运动训练对扫视皮质控制的训练效果。在8例因枕叶皮质病变导致同侧偏盲的患者中，测量了视觉引导扫视期间的脑激活情况。中风后8周开始，患者接受了4周的视野训练。fMRI测量在基线和训练后进行。在5例患者中，训练结束后4周进行了随访fMRI。使用统计参数映射软件（SPM'99）评估静息和扫视之间以及训练前后激活的差异。12名健康受试者每隔4周扫描两次。在患者中，基线时在双侧额叶和顶叶眼区（分别为FEF和PEF）以及辅助眼区（SEF）发现了显著激活。训练后立即发现，患侧半球的左侧纹外皮质激活区域增加。随访时，在右侧纹周皮质和未受影响侧的SEF中发现相对更多的激活。在左侧FEF中发现激活相对减少。在这组患者中，眼球运动训练导致纹状和纹外皮质以及动眼神经区域的脑激活发生改变。
