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Completed

NCT Number: NCT07752316

Gamma tACS to Improve Cognitive Function in Mild Cognitive Impairment

Mild cognitive impairment (MCI) is a decline in memory and thinking that exceeds normal aging but does not substantially disrupt daily life, and it raises the risk of developing dementia. Effective treatments for its cognitive difficulties are few.

This study tests whether transcranial alternating current stimulation (tACS), a non-invasive method that delivers a weak oscillating electrical current through scalp electrodes, can improve thinking and memory in older women with MCI. The current oscillates at 80 Hz, a frequency in the gamma range, because gamma brain rhythms support memory and attention and are disrupted in MCI.

Thirty older women with MCI are randomly assigned to receive either active 80 Hz tACS or sham (placebo) stimulation. Participants and the person delivering the stimulation do not know the group assignment. Both groups complete the same cognitive tests before and after the sessions, measuring overall cognitive status, planning, visuospatial working memory, and reaction speed. The aim is to determine whether active 80 Hz tACS improves cognitive performance more than sham stimulation.

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Key information

Conditions

Mild Cognitive Impairment (MCI) Cognition Disorders Cognitive Dysfunction Mental Disorders Neurocognitive Disorders

Age range

60 year–75 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Department of Psychology, University of Mohaghegh Ardabili

Ardabil, Iran

About this study

Mild cognitive impairment (MCI) is a decline in memory and thinking skills that is greater than expected for a person's age but not severe enough to interfere substantially with daily life. Older adults with MCI are at increased risk of developing dementia, and there are currently few effective treatments for the cognitive difficulties it causes.

This study tests whether a form of non-invasive brain stimulation called transcranial alternating current stimulation (tACS) can improve thinking and memory in older women with MCI. tACS delivers a weak electrical current that oscillates at a set frequency through electrodes placed on the scalp. In this study the current oscillates at 80 Hz, a frequency in the gamma range, because gamma brain rhythms are involved in memory and attention and are known to be disrupted in MCI and Alzheimer's disease.

Thirty older women with MCI are randomly assigned to one of two groups. One group receives active 80 Hz tACS and the other receives sham (placebo) stimulation, in which the device is set up identically but no meaningful current is delivered. Participants and the person delivering the stimulation do not know which group each participant is in. Both groups complete the same set of cognitive tests before and after the stimulation sessions. The tests measure overall cognitive status, planning ability, visuospatial working memory, and reaction speed.

The aim is to determine whether active 80 Hz tACS improves cognitive performance more than sham stimulation in this population.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Female, aged 60 to 75 years
  • Diagnosis of mild cognitive impairment (MCI) established by a psychiatrist and documented in the patient's medical record
  • Montreal Cognitive Assessment (MoCA) score between 16 and 22
  • Written informed consent to participate in the study
  • No history of Parkinson's disease, stroke, epilepsy, schizophrenia, or congenital olfactory and gustatory disorders

Exclusion criteria

  • Inability to tolerate the adverse effects of the stimulation
  • Unwillingness to continue the sessions
  • Absence from more than three intervention sessions

Treatment and study plan

Transcranial Electrical Stimulation

Device

Transcranial electrical stimulation (tES) is a non-invasive neuromodulation technique that applies low-intensity electrical currents to the scalp to modulate brain activity. It targets specific brain regions to influence neuronal excitability, connectivity, and plasticity, offering potential therapeutic benefits for neurological and psychiatric conditions. tES is portable, cost-effective, and generally well-tolerated, with minimal side effects such as mild tingling or itching at the stimulation site.

Primary outcomes

  1. Overall cognitive status

    Time frame: Baseline (pre-intervention), week 2 (immediately after the intervention)

    The Montreal Cognitive Assessment (MoCA) is a validated screening measure of global cognitive status, scored from 0 to 30, with higher scores indicating better cognition. Change from baseline to the post-intervention assessment is compared between the active 80 Hz tACS and sham groups.

Secondary outcomes

  1. Planning and problem-solving - Performance accuracy and reaction time

    Time frame: Baseline (pre-intervention), week 2 (immediately after the intervention)

    The Tower of London is a computerized task that assesses executive function, specifically planning and problem-solving. Higher scores indicate better planning ability. Change from baseline to the post-intervention assessment is compared between the active 80 Hz tACS and sham groups.

  2. Spatial working memory - Performance accuracy and reaction time

    Time frame: Baseline (pre-intervention), week 2 (immediately after the intervention)

    The Corsi Block-Tapping Test is a computerized task that assesses visuospatial short-term and working memory. Participants reproduce sequences of illuminated blocks of increasing length. Higher scores indicate greater visuospatial working memory capacity. Change from baseline to the post-intervention assessment is compared between the active 80 Hz tACS and sham groups.

  3. Cognitive Reaction time

    Time frame: Baseline (pre-intervention), week 2 (immediately after the intervention)

    The simple reaction time task is a computerized measure of psychomotor speed. Participants respond as quickly as possible to a stimulus that appears at unpredictable intervals. Shorter reaction times, measured in milliseconds, indicate faster psychomotor speed. Change from baseline to the post-intervention assessment is compared between the active 80 Hz tACS and sham groups

Sponsors and collaborators

Lead sponsor

The National Brain Mapping Laboratory (NBML)

Other

Collaborators

  • Mohaghegh Ardabili University
  • University Hospital, Aachen

Registry information

Official study title

Efficacy of 80 Hz Transcranial Alternating Current Stimulation (tACS) on Cognitive Function in the Elderly With Mild Cognitive Impairment

Acronym: TACS-MCI

Important dates

Study start
2024
Primary completion
2025
Study completion
2025
First posted
Aug 7, 2026
Registry last updated
Aug 7, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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