High Definition Transcranial Direct Current Stimulation (HD-tDCS) in Patients With Mild Cognitive Impairment

The Effect of High Definition Transcranial Direct Current Stimulation (HD-tDCS) on Cognitive Function in Patients With Mild Cognitive Impairment: a Randomized, Triple-blind, Sham-controlled, Pilot Study

The study aimed to investigate whether high definition transcranial direct current stimulation (HD-tDCS) could benefit global cognitive function and sub-domains of cognition (visual/verbal/working memory, executive function, attention, processing speed, language, and frontal lobe function), mood (depression and anxiety), and subjective memory impairment in patients with mild cognitive impairment.

Transcranial direct current stimulation (tDCS), a novel, non-invasive and safe neuro-modulating technique, has been developed as a new therapeutic option for neuropsychiatric disorders. It encompasses the induction of a relatively weak constant current flow through the cerebral cortex via scalp electrodes. Dependent on stimulation polarity, this results in a modulation of cortical excitability and spontaneous neural activity. Compared with tDCS, high-definition transcranial direct current stimulation (HD-tDCS) is highly focal and can specifically modulate cortical activity within the region confined by its 4 x 1 ring of elctrodes, such that the targeted region becomes more amenable to neuroplastic change. Studies have suggested that tDCS improve cognition, including memory recall, verbal fluency and executive function. Yet, there is not HD-tDCS study on MCI. The purpose of this study is to examine whether HD-tDCS could benefit global cognitive function and sub-domains of cognition (visual/verbal/working memory, executive function, attention, processing speed, language, and frontal lobe function), mood (depression and anxiety), and subjective memory impairment in patients with mild cognitive impairment.

Inclusion Criteria:

• Aged 65 to 85 years
• mild cognitive impairment
• right handed

Exclusion Criteria:

• Having epilepsy, severe physical illness, any current psychiatric comorbidity or history of substance dependence
• Having contraindications for transcranial electrical/magnetic stimulation.
• Having intracranial metal foreign bodies
• Having a history of intracranial neoplasms or surgery, or a history of severe head injuries or cerebrovascular diseases
• Receiving psychotropic agents such as antipsychotic, antidepressant, benzodiazepam and anxiolytics etc.