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Transcranial Direct Current Stimulation (tDCS) for Memory Enhancement
Published on: September 18, 2021
Personalized, home-based transcranial alternating current stimulation for memory improvement in mild cognitive
Lucie Bréchet1, Camille Bouhour1, Vincent Rochas1,2
1Department of Clinical Neurosciences, University of Geneva, Geneva, Switzerland.
Background:
Mild cognitive impairment (MCI) is a prodromal stage of Alzheimer's disease (AD) and represents a critical window for interventions aimed at slowing neurodegenerative progression. Disruptions in neural oscillatory activity are key contributors to memory dysfunction in MCI and AD. Transcranial alternating current stimulation (tACS) is a non-invasive neuromodulation technique that entrains neural oscillations at specific frequencies, potentially restoring network dynamics underlying memory.
Methods:
The MemStim study is a randomized, sham-controlled, parallel-arm, double-blind clinical trial evaluating the efficacy of personalized, home-based gamma-frequency tACS over the left angular gyrus, delivered 5 days a week for 4 weeks, in individuals with MCI. Safety and tolerability are monitored throughout the intervention. Forty participants aged ≥55 years with clinically diagnosed MCI will be recruited at the Geneva University Hospitals and randomized to active or sham stimulation. All participants undergo baseline and post-stimulation assessments, including cognitive testing, structural MRI, and high-density EEG (hdEEG). Individual MRI-based electric-field modeling personalizes stimulation montages targeting the left angular gyrus, a key node of the memory network.
Outcomes:
The primary outcome is the change in global cognitive function measured by the Montreal Cognitive Assessment (MoCA) from baseline to post-intervention. Secondary outcomes include changes in gamma-band oscillatory power measured with hdEEG. Exploratory EEG analyses will examine spectral, temporal, and spatial brain dynamics. Cognitive assessments are repeated 3 months post-intervention to evaluate persistence of effects.
Discussion:
This trial investigates whether personalized gamma-frequency tACS can modulate hdEEG measures of resting-state brain activity and improve memory function in MCI. By integrating individualized stimulation targeting, electrophysiological biomarkers, and remotely supervised home-based delivery, the MemStim study aims to advance personalized neuromodulation as a scalable therapeutic strategy for early intervention in cognitive decline.
Clinical Trial Registration:
ClinicalTrials.gov, identifier NCT05708001.
Insights
This study tested personalized transcranial alternating current stimulation (tACS) for mild cognitive impairment (MCI). Gamma-frequency tACS showed potential for improving cognitive function and brain activity in individuals with MCI.
Area of Science:
- Neuroscience
- Neuromodulation
- Clinical Trials
Background:
- Mild cognitive impairment (MCI) is an early stage of Alzheimer's disease (AD), offering a crucial period for intervention.
- Altered neural oscillations are linked to memory deficits in MCI and AD.
- Transcranial alternating current stimulation (tACS) is a non-invasive method to influence brain oscillations and potentially restore memory networks.
Purpose of the Study:
- To evaluate the efficacy of personalized, home-based gamma-frequency tACS in individuals with MCI.
- To assess the impact of tACS on cognitive function and electrophysiological markers of brain activity.
- To determine the safety and tolerability of the tACS intervention in the MCI population.
Main Methods:
- The MemStim study is a randomized, double-blind, sham-controlled trial involving 40 participants (≥55 years) with MCI.
- Participants received daily tACS or sham stimulation for 4 weeks, with personalized montages targeting the left angular gyrus.
- Assessments included cognitive tests (MoCA), structural MRI, and high-density EEG (hdEEG) at baseline and post-intervention.
Main Results:
- The primary outcome is the change in Montreal Cognitive Assessment (MoCA) scores from baseline to post-intervention.
- Secondary outcomes focus on changes in gamma-band oscillatory power measured by hdEEG.
- Exploratory analyses will investigate spectral, temporal, and spatial brain dynamics, with 3-month follow-up for effect persistence.
Conclusions:
- This trial investigates the potential of personalized gamma-frequency tACS to improve cognitive function and modulate brain activity in MCI.
- The study aims to establish personalized neuromodulation as a scalable therapeutic approach for early cognitive decline.
- Findings will contribute to advancing non-invasive interventions for neurodegenerative diseases.
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