Effects of tDCS on Cognition in MCI: A RCT

Plain-language summary

MCI is considered an intermediate stage between normal cognitive aging and dementia. As such, improving cognitive functions of people with MCI may delay dementia onset. In recent years, tDCS, which regulates brain activity by increasing or decreasing brain tissue excitability, has become a commonly used brain stimulation method. Accumulating evidence indicates the promising effects of cognitive enhancement after tDCS over the frontal scalp regions in people with MCI (PwMCI). However, previous studies were limited by including only a self-report measure, focused on memory performance, not assessing long-term effect, and not reporting their results in follow-up. In addition, knowledge of the precise physiological consequences of tDCS on the brain tissue and related neural mechanisms in PwMCI remains rudimentary. The objectives of the proposed study, which will target PwMCI, are to investigate the effects of tDCS at the left dorsolateral prefrontal cortex on the cognitive performance and to explore the modulation of neural mechanisms associated with the use of tDCS. Forty-eight MCI participants aged over 60 years will be recruited. All participants will be assessed by Hong Kong version of Montreal Cognitive Test. Participants that meet selection criteria will be invited to the experiment. Participants will be assigned to experimental or control groups randomly. The experiment will consist of pre- and post-assessments and a 1-month follow-up assessment. Between pre- and post-assessments, participants will receive 8 sessions (2x/week for 4 weeks) of tDCS treatment (either real or sham, 20 min per session). Outcome measures include digit span test, colour trail test, verbal fluency test, Chinese version of the Verbal Learning Test , and Hong Kong version of Montreal Cognitive Assessment. Participants will also complete a computer memory task at each assessment point (performance in this task is also used as an outcome measure) and will have their brain wave recorded while completing the task. The task will require them to study and memorise Chinese characters, followed by a recognition memory test. In the study phase, participants will be required to view Chinese characters and judge whether the characters are of the animal category. In the recognition phase, participants will decide whether the characters have been seen before.

Who can participate

What they're measuring

Trial details