Effects of Transcranial Direct Current Stimulation (tDCS) on Brain Organization and Naming
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 14
- 试验地点
- 2
- 主要终点
- Action picture naming, short-term improvement
研究概览
简要总结
High-Definition Transcranial Direct Current Stimulation (HD-tDCS) allows to induce, in a non-invasive way, a transient inhibitory or excitatory neuromodulation of a given cerebral region and to obtain a very focused cortical effect. Previous studies using HD-tDCS have shown the effectiveness of this stimulation technique for enhancing language recovery in patients with aphasia.
However, language processes are not determined solely by local neural activity at a single site, but rather by the interaction between neural networks. This is because a large cortical network is involved in language processes and, therefore, the same language disorder may result from lesions at different locations in this network.
The investigators hypothesize that anodal HD-tDCS will enhance neural interactions between language areas and, thereby, improve language processing and word learning.
The investigators propose to carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.
详细描述
Functional connectivity (FC) represents a means of analyzing functional interactions in the brain network by assessing the statistical dependence of neural activity between brain areas. The brain maintains a high level of interactions between brain areas even in the resting state, when it is not explicitly involved in a specific task. Resting-state interactions occur mainly in the so-called alpha frequency band (8-13 Hz) . Moreover, these resting-state interactions are crucial for correct task performance and learning. Indeed, healthy subjects with high resting-state alpha-band FC levels are better able to perform tasks and learn. For example, subjects with high levels of FC between Broca's area and the rest of the brain perform better on language production tasks and show greater training gains when learning new words. In addition, patients with brain damage due to stroke show a reduction in resting-state alpha-band FC, which correlates with the severity of neurological deficits. In particular, a loss of FC of structurally preserved inferior frontal areas was associated with more severe aphasia. Conversely, high-levels of FC between the inferior frontal brain areas and the rest of the brain during the first weeks after stroke was associated with better recovery from aphasia, probably reflecting a reorganization of neural connections as a neural mechanism involved in plasticity. Resting-state FC is therefore an interesting neural target for therapy, which could help improve recovery from aphasia.
In a previous study on healthy subjects, the investigators have indeed observed that HD-tDCS applied to Broca's area improves the ability for new-verb learning, i.e., the correct naming of action pictures. This improvement in learning correlated with greater increase in FC between Broca's and Wernicke's area.
The investigators now carry out a study on chronic aphasic patients involving HD-tDCS of the Broca region (left inferior frontal gyrus) combined with a verb learning task.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Double (Participant, Outcomes Assessor)
盲法说明
sham-tDCS
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Ischemic or hemorrhagic stroke
- •Presence of aphasia with difficulty finding words and/or naming objects/pictures
- •≥12 months post-stroke
- •≥ 18 years of age
- •French-speaking
- •Able to participate in 30-60 min therapeutic sessions (good concentration and understanding of the task and ability to follow instructions
排除标准
- •Patients unable to understand the given information on the study and its objectives, or instructions for tasks performed.
- •Impaired alertness or delirium
- •Severe co-morbidity affecting speech
- •Contraindication to tDCS: pregnant women, patients with active implants such as pacemakers or cochlear implants, patients with one or more seizures, metal objects in the brain
- •Occurrence of a new stroke during the study protocol.
研究组 & 干预措施
HD-tDCS
high-density transcranial direct current stimulation (HD-tDCS) over Broca's area
干预措施: HD-tDCS (Device)
sham-tDCS
sham transcranial direct current stimulation. The same setup will be used as in the HD-tDCS arm, except that the current will be ramped up for 30 seconds and then switched off. This does not lead to neural effects, but the patients have a similar sensation.
干预措施: HD-tDCS (Device)
结局指标
主要结局
Action picture naming, short-term improvement
时间窗: Change from day 1 (baseline) to day 5 (posttest)
Change in number of correctly named action pictures
次要结局
- Functional connectivity between Broca's and Wernicke's area(Change from day 1 (baseline) to day 5 (posttest))
研究者
Adrian Guggisberg
Médecin conseil
University Hospital, Geneva