The Effect of Transcranial Direct Current Stimulation on Visual Attention in Mild Cognitive Impairment
The Effect of Transcranial Direct Current Stimulation on Visual Attention in Mild Cognitive Impairment
Progressively causes the breakdown of cognitive functions and impairs quality of life for
 patients and their caregivers. In addition to memory impairment, visual attention is also
 compromised, even at the stage of mild cognitive impairment due to AD (MCI-AD). No treatment
 has been found for MCI-AD; therefore, attention has been drawn to non-invasive brain
 stimulation techniques, such as transcranial direct current stimulation (tDCS), in order to
 enhance cognitive functions by modifying brain plasticity. In the current research,
 investigator aim to examine the long-term effects of the optimal multiple-session tDCS
 protocol in MCI-AD on visual attention including the transfer to an ecologically valid
 virtual environment and identify the neural underpinnings of tDCS-induced behavioral
 aftereffects using a combined tDCS/ MRI network-based approach.
Investigator will investigate the long-term effects of 10 active tDCS consecutive sessions
 using an optimized stimulation protocol as compared to a placebo stimulation on visual
 attention in the MCI-AD. A two-parallel-group, randomized, placebo-controlled design will be
 used. In addition, the cognitive transfer of tDCS will be evaluated. Repeated tDCS sessions
 will be performed in 10 consecutive sessions (2 weeks: Monday to Friday) over one preselected
 ROI together with ongoing visual attention training. During the stimulation, investigator
 will use the visual matching task. Before the repeated stimulation sessions, participants
 will undergo the neurocognitive examination. Behavioral examinations of the trained and
 untrained tasks (i.e. the transfer tasks) will be performed to assess the baseline
 performance. MRI protocol consisting of T1, T2, FLAIR, and fMRI during the task performance
 (visual matching task), resting state fMRI, and DTI sequences will be acquired before and
 after the whole 10-day stimulation protocol in order to search for active vs. placebo
 tDCS-induced changes in brain activation and resting state functional and structural
 connectivity and to identify neural correlates of behavioral changes. Behavioral assessment
 of the trained task and the transfer task will be repeated immediately after and again at a
 one-month follow-up visit after the end of the last stimulation session
Inclusion Criteria:

 -  amnestic single or multi-domain mild cognitive impairment patients in accordance with
 diagnostic criteria (Albert et al., 2011)

 Exclusion Criteria:

 -  psychiatric disorders, including major depression, major vascular lesions, and other
 brain pathologies detected by MRI that might present with cognitive decline

 -  a cardio pacemaker or any MRI-incompatible metal in the body

 -  epilepsy

 -  any diagnosed psychiatric disorder

 -  alcohol/drug abuse

 -  lack of cooperation

 -  presence of dementia.