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.
Older adults with Mild Cognitive Impairment (MCI) exhibit reduced brain alpha power (i.e., activity fluctuations in the 8-13 Hz range) compared to healthy older adults, and older adults who exhibit lower alpha activity in the fronto-central areas tend to have impaired executive function. In addition, our group has demonstrated that older adults who exhibit lower fronto-central alpha power during dual-task standing (i.e., standing while performing an unrelated cognitive task) have worse standing balance performance. We, therefore, contend that strategies designed to increase alpha power in older adults with MCI hold promise to enhance dual-task balance and other measures of executive function, and ultimately help these vulnerable individuals maintain functional independence over time. In our preliminary studies, we have demonstrated that a single exposure to transcranial alternating current stimulation (tACS) delivered at 10 Hz over the fronto-central regions of the brain increases alpha power and dual-task balance in older adults with MCI, when tested just after stimulation. We have also observed that in older adults with MCI, 10 Hz tACS appears to have a greater effect on alpha activity and dual-task balance in those individuals whose peak alpha frequency happens to be at or near the stimulation frequency (10 Hz). Given the above evidence, we will conduct a pilot, double-blinded, parallel-arm, randomized controlled trial in ambulatory women and men aged 65-85 years with MCI. Our primary hypothesis is that compared to sham, tACS will improve dual-task balance when tested at the end of the intervention, and that such effects will persist at the 1- and 3-month follow-up. We further hypothesize that 1) tACS, compared to sham, will improve performance in other clinically-tractable measures of executive function and mobility, and 2) that tACS-induced improvements in dual-task balance will correlate with increased alpha brain activity. Through these efforts, we anticipate providing rigorous preliminary data that individually-tailored tACS is an effective therapeutic option capable of inducing sustained improvements in cognitive-motor functions, as well as underlying brain activity, in older adults with MCI.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
20
High Point University
High Point, North Carolina, United States
RECRUITINGEEG alpha-band power
Change of EEG oscillations and frequency coupling at 8-13 Hz
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Change of postural sway speed
his metric assesses the ability to control standing posture
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Change of executive function score
This metric reflects measures of executive function scores based on individual neuropsychological test of Trail-making Test B completion time
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Change of dual-task gait speed
This metric (m/s) assesses the ability to walk and perform a cognitive task at the same time and predicts cognitive decline and the development of dementia.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Timed Up and Go Test completion time
This test assesses time to complete standing from a chair, walking three meters, turning around a cone and returning to a seated position in the chair.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Short Physical Performance Battery score
This common test assesses physical functioning. The score is ranging from 0 to 12, with higher scores indicating better physical performance.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Montreal Cognitive Assessment (MoCA)
This common test assesses global cognitive function. The Montreal Cognitive Assessment (MoCA) test is scored out of a total of 30 points, with higher scores indicating better cognitive function.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Dual-task Standing Postural Sway Path
This metric assesses the ability to stand and perform a cognitive task at the same time and predicts cognitive decline and the development of dementia.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Serial subtraction test performance
This metric assesses the number of correct response on serial subtraction test while standing
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Digit Span total recall
This metric assesses working memory.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
WAIS-IV Coding test completion time
This metric assesses sustained attention and motor speed.
Time frame: Baseline, immediate post-intervention assessments, Follow-up visit #1 (4 weeks later of post-intervention assessment, Follow-up visit #2 (12 weeks later post-intervention assessment).
Brain networks connectivity changes
Measures of functional brain connectivity based on resting-state functional magnetic resonance imaging.
Time frame: Baseline and immediate post-intervention assessments
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