Multi-session Transcranial Alternating Current Stimulation to Improve Dual-task Standing and Brain Activity in Older Adults With Mild Cognitive Impairment

Older adults with Mild Cognitive Impairment (MCI) often show less brain activity in a specific range (8-13 Hz, known as alpha power) compared to healthy older adults. Those with lower alpha activity, especially in the front part of the brain, usually have problems with executive functions like planning and multitasking. Our research has shown that older adults with lower alpha power in these areas also struggle more with balance when they have to do two things at once (like standing and performing a cognitive task simultaneously). The investigators believe that increasing alpha power in older adults with MCI could improve their balance and executive function, helping them stay independent longer. In early studies, the investigators found that using transcranial alternating current stimulation (tACS) at 10 Hz on the front part of the brain can boost alpha power and balance immediately after a single session in older adults with MCI. The effect was stronger in those whose natural brain activity was close to the 10 Hz stimulation. Based on these findings, the investigators plan to conduct a pilot study with older adults aged 65-85 years with MCI. Participants will be randomly assigned to receive either real tACS or a sham (placebo) treatment. Our main hypothesis is that real tACS will improve balance when multitasking, and these improvements will last for 1 to 3 months after the treatment. The investigators also believe that tACS will enhance other aspects of executive function and mobility and that these improvements will be linked to increased alpha activity in the brain. Through this study, we aim to gather strong evidence that tailored tACS is a promising treatment to improve cognitive and motor functions and overall brain activity in older adults with MCI.