Brain mechanisms underlying reading improvement in post-stroke central alexia

中枢性失读症是一种常见的阅读障碍，由中风和其他形式的脑损伤引起。中枢性失读症患者阅读速度慢，阅读时会出错。他们的语言也有其他问题，最常见的是。阅读对大多数人来说很重要，所以中枢性失读症患者在重返工作岗位、通过电子邮件或短信交流或只是为了娱乐而阅读方面存在困难。本研究有四个目标，具体描述如下。研究支持中风患者阅读的神经网络尽管这是一种相对常见的综合征，但还没有关于中枢性失读症的脑功能成像研究。这个研究项目的主要目的是使用功能成像来了解如何通过治疗来鼓励阅读网络中被保留的部分，以支持再次阅读。这将通过使用脑磁图(MEG)进行网络连通性分析的最先进技术来完成。脑磁图以毫秒级的高精度时间分辨率检测大脑活动的变化，这使其成为研究阅读的理想工具(在低于20ms的曝光下可以识别单词)。我们之前使用脑磁图进行的研究已经确定了形成“正常”阅读网络的大脑区域，拟议中的研究将测试这一模型在中枢失调症患者中是如何受到影响的。开发一种治疗中枢性失读症的新方法目前还没有针对中枢性失读症的简单治疗方法，而且之前只有两个小组水平的阅读训练研究在这一患者组中进行。我们计划开发一个基于计算机的阅读训练系统，以提高中枢性失读症患者的单词阅读速度。研究团队开发了一款名为iReadMore的训练软件，该软件使用密集的跨模式方法(视觉书面单词与听觉口语单词配对)来训练单词阅读。这种疗法已经被证明对一组患有类似形式的阅读障碍的患者有效，这种障碍被称为纯失读症。IReadMore软件将被用来解决中部失读症患者的阅读障碍，这项研究将测试它是否会显著提高阅读速度，从而改变患者的生活。使用脑刺激来加强行为训练经颅直流电刺激(Tdcs)是一种相对较新的脑刺激技术，已被证明可以改善健康对照组和中风患者的语言能力。它还没有被应用于后天阅读障碍的治疗。这项研究将测试与iReadMore阅读训练同时进行的tdcs是否显著提高了阅读速度。为此，参与研究的患者将被分成两组。其中一组将接受为期4周的训练，并首先接受真正的tDCs；另一半将接受同样的训练，但使用与真正的大脑刺激没有区别的“假”tDCs。然后，两组将在第二个为期4周的区块中互换，以便两组最终得到相同的治疗量。比较真实的和假的tdcs区块的阅读改善将证明tdcs是否提高了阅读速度的行为改善。为中枢性失读症开发基于网络的治疗目前还没有基于网络的治疗辅助工具供中枢性失读症患者自己使用。。如果iReadMore被证明是有效的，并被患者接受，那么我们计划通过网络浏览器提供给合适的患者使用。我们在这一领域有着良好的业绩记录，并已经为中风后视力障碍患者开发了两款高质量的治疗“网络应用”：www.readright.ucl.ac.uk和www.eyesearch.ucl.ac.uk。

Central alexia is a common reading disorder caused by stroke and other forms of brain injury. Patients with central alexia are slow to read and make errors when they do so. They also have other problems with their language, most commonly speaking. Reading is important to most people so patients with central alexia have trouble returning to work, communicating by email or text, or simply reading for pleasure. The present research has four aims, described in detail below.1. Investigating the neural networks that support reading in patients with strokeDespite being a relatively common syndrome, there have been no functional brain imaging studies of central alexia. The primary aim of this research project is to use functional imaging to understand how preserved parts of the reading network can be encouraged by therapy to support reading again. This will be done with a state-of-the-art technique of network connectivity analysis using magnetoencephalography (MEG). MEG detects changes in brain activity with a highly precise time resolution at the millisecond range, which makes it ideal for investigating reading (words can be recognized at exposures of less than 20ms). Our previous research using MEG has identified brain areas that form the 'normal' reading network, and the proposed study will test how this model is affected in patients with central alexia.2. Developing a new treatment for central alexiaThere are currently no easy-to-access therapies for central alexia, and only two previous group-level studies of reading training have been conducted in this patient group. We plan to develop a computer-based reading training system to improve word reading speed in patients with central alexia. The research team has developed training software called 'iReadMore', which uses an intensive cross-modal approach (visual written words paired with auditory spoken words) to train word reading. This therapy has been shown to be effective in a group of patients with a similar form of reading disorder called pure alexia. The iReadMore software will be adapted to address the reading deficit in central alexia, and the research will test whether it leads to significant improvements in reading speed that makes a difference to patients' lives.3. Using brain stimulation to enhance behavioural trainingTranscranial direct current stimulation (tDCS) is a relatively new brain stimulation technique that has been shown to improve language performance in healthy controls and stroke patients. It has not yet been applied to the treatment of acquired reading disorders. The present study will test whether tDCS, delivered simultaneously with the 'iReadMore' reading training, significantly enhances the improvement in reading speed. To do this, the patients participating in the study will be split into two groups. One group will receive a 4-week block of training plus real tDCS first; and the other half will receive the same training but with 'sham' tDCS that is indistinguishable to the real brain stimulation. The two groups will then swap over in the second 4-week block, so that both groups ultimately get the same amount of treatment. Comparing the reading improvement over the real and sham tDCS blocks will demonstrate whether tDCS enhances the behavioural improvements in reading speed.4. Developing web-based therapy for central alexiaThere are currently no web-based therapy aids for patients with central alexia to access for themselves. . If 'iReadMore' proves effective and acceptable to patients then we plan to make it available via a web browser for suitable patients to use. We have a proven track record in this area and have already produced two high-quality, therapy "web-apps", www.readright.ucl.ac.uk and www.eyesearch.ucl.ac.uk, for patients with visual impairment after stroke.