Rode Gilles, Klos Thomas, Courtois-Jacquin Sophie, Rossetti Yves, Pisella Laure
Service de Rééducation Neurologique, Hospices Civils de Lyon, Hôpital Henry Gabrielle, St Genis Laval, France.
Restor Neurol Neurosci. 2006;24(4-6):347-56.
A large proportion of right-hemisphere stroke patients show unilateral neglect, a neurological deficit of perception, attention, representation, and/or performing actions within their left-sided space, inducing many functional debilitating effects on everyday life, and responsible for poor functional recovery and ability to benefit from treatment. This spatial cognition disorder affects the orientation of behaviour with a shift of proprioceptive representations toward the lesion side.
This shift can be reduced after a prism adaptation period to a right lateral displacement of visual field (induced by a simple target-pointing task with base-left wedge prisms). The modification of visuo-motor or sensory-motor correspondences induced by prism adaptation involves improvement of different symptoms of neglect.
Classical visuo-motor tests could be improved for at least 2h after adaptation, but also non-motor and non-visual tasks. In addition, cross-modal effects have been described (tactile extinction and dichotic listening), mental imagery tasks (geographic map, number bisection) and even visuo-constructive disorders. These cognitive effects are shown to result from indirect bottom-up effects of the deeper, adaptive realignment component of the reaction to prisms. Lesion studies and functional imaging data evoke a cerebello-cortical network in which each structure plays a specific role and not all structures are crucial for adaptation ability.
These cognitive effects of prism adaptation suggest that prism adaptation does not act specifically on the ipsilesional bias characteristic of unilateral neglect but rehabilitates more generally the visuo-spatial functions attributed to the right cortical hemisphere. These results reinforce the idea that the process of prism adaptation may activate brain functions related to multisensory integration and higher spatial representations and show a generalization at a functional level. Prism adaptation therefore appears as a new powerful therapeutic tool for spatial cognition disorders.
很大一部分右半球中风患者表现出单侧忽视，这是一种神经感知缺陷，表现为在其左侧空间内的感知、注意力、表征和/或执行动作方面存在问题，会对日常生活产生许多功能衰弱影响，并导致功能恢复不佳以及从治疗中获益的能力受限。这种空间认知障碍会影响行为的定向，使本体感觉表征向病变侧偏移。
在经过一段棱镜适应期（通过使用左基底楔形棱镜的简单目标指向任务诱导视野向右外侧移位）后，这种偏移可以减少。棱镜适应所诱导的视觉运动或感觉运动对应关系的改变涉及忽视不同症状的改善。
经典的视觉运动测试在适应后至少2小时内可以得到改善，非运动和非视觉任务也能改善。此外，还描述了跨模态效应（触觉消退和双耳分听）、心理意象任务（地理地图、数字平分）甚至视觉构建障碍。这些认知效应被证明是由对棱镜反应的更深层次适应性重新调整成分的间接自下而上效应导致的。病变研究和功能成像数据引发了一个小脑 - 皮质网络，其中每个结构都发挥着特定作用，并非所有结构对于适应能力都至关重要。
棱镜适应的这些认知效应表明，棱镜适应并非专门作用于单侧忽视的同侧偏向特征，而是更普遍地恢复了归因于右皮质半球的视觉空间功能。这些结果强化了这样一种观点，即棱镜适应过程可能激活与多感官整合和更高空间表征相关的脑功能，并在功能层面显示出一种泛化。因此，棱镜适应似乎是一种治疗空间认知障碍的新的有力治疗工具。
