Nebel Katharina, Wiese Holger, Seyfarth Julia, Gizewski Elke R, Stude Philipp, Diener Hans-Christoph, Limmroth Volker
Department of Neurology, University of Duisburg-Essen, Hufelandstr. 55, 45122 Essen, Germany.
Brain Res. 2007 Jun 2;1151:150-60. doi: 10.1016/j.brainres.2007.03.007. Epub 2007 Mar 12.
It was investigated whether the cortical activity during tasks requiring focused or divided attention is reduced in multiple sclerosis patients with prominent deficits (MS(+D)) and increased in patients without impairment (MS(-D)) in these specific attention functions.
Six MS(+D) patients with attention deficits, six unimpaired MS(-D) patients, and age-, gender-, and education-matched healthy control subjects were examined with functional magnetic resonance imaging (fMRI). The experimental paradigm consisted of visual tasks requiring focused or divided attention.
Performance accuracy and reaction times were impaired in MS(+D) patients. This subgroup showed reduced activation within superior and inferior frontal gyrus during focused attention. Under conditions of divided attention decreased activity was found within middle and inferior frontal gyrus, inferior parietal structures, and occipital areas. No compensatory activity was observed. MS(-D) patients did neither differ in behavioral data nor in cortical activity in attention related structures from control subjects.
The study found evidence for the neural correlate of attentional deficits in MS patients. In patients with specific attention deficits, reduced cortical activity in prefrontal and parietal areas, which are associated with attention and executive control, reflects the patients' reduced performance on a behavioral level. Our findings also suggest impaired top-down attentional control on sensory structures in these patients. In patients without verifiable attention deficits a normal functioning of structures relevant for executive attention was observed. Compensatory activity in these structures as a marker of reorganization in less pronounced stages of the disease was not found.
研究在需要集中或分散注意力的任务中，具有明显缺陷的多发性硬化症患者（MS(+D)）的皮层活动是否减少，而在这些特定注意力功能方面无损伤的患者（MS(-D)）的皮层活动是否增加。
对6名有注意力缺陷的MS(+D)患者、6名无损伤的MS(-D)患者以及年龄、性别和教育程度相匹配的健康对照者进行功能磁共振成像（fMRI）检查。实验范式包括需要集中或分散注意力的视觉任务。
MS(+D)患者的表现准确性和反应时间受损。该亚组在集中注意力时，额上回和额下回内的激活减少。在分散注意力的条件下，额中回和额下回、顶下结构以及枕叶区域的活动减少。未观察到代偿性活动。MS(-D)患者在行为数据以及与注意力相关结构的皮层活动方面与对照者均无差异。
该研究发现了MS患者注意力缺陷的神经相关性证据。在有特定注意力缺陷的患者中，与注意力和执行控制相关的前额叶和顶叶区域皮层活动减少，反映了患者在行为水平上的表现下降。我们的研究结果还表明，这些患者对感觉结构的自上而下的注意力控制受损。在无可证实的注意力缺陷的患者中，观察到与执行性注意力相关结构的功能正常。未发现这些结构中的代偿性活动作为疾病不太明显阶段重组的标志。
