Division of Neurorehabilitation, University Hospitals of Geneva, 26, Av. de Beau-Séjour, CH-1211 Geneva 14, Switzerland.
J Neurol Neurosurg Psychiatry. 2011 Nov;82(11):1279-82. doi: 10.1136/jnnp-2011-300656. Epub 2011 Jul 11.
Patients with left neglect direct their attention too strongly to the right. Hypotheses hold that this is due to a failure to disengage attention from right-sided stimuli or to a directional bias of attention into right space.
To test how persistence versus absence of visual distracters, which the patients themselves placed on a screen, influenced the expression of neglect.
13 patients with left neglect and six right-hemisphere-damaged control patients without neglect were asked to evenly distribute 120 dots on a screen by clicking the computer mouse. In the Feedback condition, dots remained visible; in the No-feedback condition, the screen remained blank throughout the task.
The two conditions strikingly dissociated from each other in neglect patients but not in controls. In the Feedback condition, neglect patients placed initial dots with a rightward shift and then maintained this spatial bias till the end of the task. In the No-feedback condition, by contrast, they placed dots much more evenly over the whole screen; indeed, the right spatial bias typical of hemispatial neglect virtually disappeared when there was no visual feedback about the dot placements.
Absence of visual feedback about the location of self-placed stimuli markedly attenuated hemispatial neglect. The finding is compatible with impaired disengagement as the prevailing factor of visual neglect and may have therapeutic consequences.
左侧忽略症患者会过于强烈地将注意力集中在右侧。假设这是由于无法将注意力从右侧刺激物上转移开，或者注意力偏向右侧空间。
测试视觉干扰物的持续存在与否（患者自己将这些干扰物放在屏幕上）如何影响忽略症的表现。
13 名左侧忽略症患者和 6 名右侧半球损伤但无忽略症的对照组患者被要求通过点击鼠标在屏幕上均匀分布 120 个点。在反馈条件下，点保持可见；在无反馈条件下，整个任务期间屏幕保持空白。
这两种情况在忽略症患者中明显不同，但在对照组中没有。在反馈条件下，忽略症患者最初将点向右移动，然后一直保持这种空间偏向，直到任务结束。相比之下，在无反馈条件下，他们将点更均匀地分布在整个屏幕上；实际上，当没有关于点放置的视觉反馈时，半空间忽略症的典型右侧空间偏向几乎消失了。
自我放置刺激物的位置没有视觉反馈，这明显减轻了半空间忽略。这一发现与注意力难以转移是视觉忽略的主要因素相一致，并且可能具有治疗意义。
