32 Participants Needed

Brain Stimulation for Working Memory

AO
HE
Overseen ByHamdi Eryilmaz, Ph.D.

Trial Summary

What is the purpose of this trial?

This study will use novel transcranial alternating current stimulation (tACS) protocols and electroencephalography (EEG) to modulate and measure brain oscillations that underlie working memory. tACS is a noninvasive method used to modulate the timing and patterns of brain rhythms via weak electric currents passed through electrodes on the scalp.

Will I have to stop taking my current medications?

Yes, you will need to stop taking certain medications, especially those that affect brain stimulation, like psychotropic drugs and others that alter brain chemicals. It's best to discuss your specific medications with the trial team.

What data supports the effectiveness of the treatment Transcranial Alternating Current Stimulation (tACS) for improving working memory?

Research suggests that tACS can have small-to-medium positive effects on working memory, especially when using specific frequencies like theta and gamma. These effects have been observed in both healthy adults and those with cognitive deficits, indicating potential for tACS as a non-drug method to enhance cognitive performance.12345

Is transcranial alternating current stimulation (tACS) safe for humans?

Research suggests that tACS is generally safe for humans, with studies highlighting its non-invasive nature and good tolerability. It has been used in various populations, including healthy adults and those with cognitive impairments, without significant safety concerns.23678

How does the treatment Active tACS differ from other treatments for working memory issues?

Active tACS (Transcranial Alternating Current Stimulation) is unique because it uses specific frequencies to modulate brain waves, potentially enhancing working memory by aligning with natural brain oscillations. Unlike other treatments, it is non-invasive, cost-effective, and has a promising safety profile, making it an attractive option for cognitive enhancement, especially in older adults and those with cognitive deficits.12359

Research Team

HE

Hamdi Eryilmaz, Ph.D.

Principal Investigator

Massachusetts General Hospital

Eligibility Criteria

This trial is for individuals who can give informed consent and are fluent in English. It's designed to explore how working memory functions by using a noninvasive brain stimulation technique.

Inclusion Criteria

Fluent in English.
Able to provide informed consent

Exclusion Criteria

Contraindications for tACS (e.g., history of seizures, metallic implants in the head or neck, implanted brain stimulators, vagus nerve stimulators, pacemakers, pregnancy)
History of a neurological/psychiatric disorder
I am currently taking medication for my mental health.
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Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants undergo four tACS sessions with EEG recording before and after each session

4 sessions over 4 weeks
4 visits (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment

2 weeks

Treatment Details

Interventions

  • Active tACS
  • Placebo tACS
Trial OverviewThe study tests two types of transcranial alternating current stimulation (tACS): 'Active tACS' which actually modulates brain activity, and 'Placebo tACS', which does not have an active effect. The impact on working memory will be measured with EEG.
Participant Groups
4Treatment groups
Experimental Treatment
Placebo Group
Group I: Theta-nested gamma tACS applied during passive task epochsExperimental Treatment1 Intervention
Participants will receive single-session administration of tACS during performance of a working memory task. tACS will be applied during fixation periods between consecutive task trials. EEG will be acquired before and immediately after the intervention.
Group II: Theta-nested gamma tACS applied during memory delaysExperimental Treatment1 Intervention
Participants will receive single-session administration of tACS during performance of a working memory task. tACS will be applied during memory delays. EEG will be acquired before and immediately after the intervention.
Group III: Gamma tACS applied during memory delaysExperimental Treatment1 Intervention
Participants will receive single-session administration of tACS during performance of a working memory task. tACS will be applied during memory delays. The stimulation will be phase locked to the peaks of ongoing theta rhythms of the participant. EEG will be acquired before and immediately after the intervention.
Group IV: Placebo tACS applied during task performancePlacebo Group1 Intervention
Participants will receive single-session administration of placebo tACS during performance of a working memory task. EEG will be acquired before and immediately after the intervention.

Active tACS is already approved in United States, European Union for the following indications:

🇺🇸
Approved in United States as Active tACS for:
  • Investigational for cognitive rehabilitation in neurodegenerative diseases and aging-related cognitive decline
🇪🇺
Approved in European Union as Active tACS for:
  • Investigational for cognitive rehabilitation in neurodegenerative diseases and aging-related cognitive decline

Find a Clinic Near You

Who Is Running the Clinical Trial?

Massachusetts General Hospital

Lead Sponsor

Trials
3,066
Recruited
13,430,000+

Findings from Research

Transcranial alternating current stimulation (tACS) at a frequency tailored to individual brain activity (Tuned condition) significantly improved visuospatial working memory (vsWM) and mental rotation tasks in 20 adults, compared to a sham stimulation.
The improvement in performance was linked to increased synchrony in the fronto-parietal brain network, suggesting that targeted stimulation can enhance specific cognitive functions related to spatial abilities.
Individually tuned theta HD-tACS improves spatial performance.Zhang, DW., Moraidis, A., Klingberg, T.[2023]
Transcranial Alternating Current Stimulation (tACS) has shown a small-to-medium effect on improving both working memory (WM) and long-term memory (LTM) in healthy adults, based on a systematic review of 104 studies.
Specific tACS parameters, such as posterior theta-tACS for WM and anterior gamma-tACS for LTM, were found to effectively modulate memory performance, with results correlating with brain oscillatory activity measured by EEG and MEG.
The effects of transcranial alternating current stimulation on memory performance in healthy adults: A systematic review.Booth, SJ., Taylor, JR., Brown, LJE., et al.[2022]
Transcranial alternating-current stimulation (tACS) is a promising non-invasive brain stimulation technique that may enhance working memory (WM) performance, particularly in older adults and individuals with cognitive deficits, due to its superior safety and tolerability compared to repetitive transcranial magnetic stimulation (rTMS).
Research indicates that tACS can effectively manipulate brain oscillations associated with WM, suggesting its potential as a non-pharmacological tool for cognitive rehabilitation in aging populations and those with conditions like dementia and depression.
Working Memory and Transcranial-Alternating Current Stimulation-State of the Art: Findings, Missing, and Challenges.Al Qasem, W., Abubaker, M., Kvašňák, E.[2023]

References

Individually tuned theta HD-tACS improves spatial performance. [2023]
The effects of transcranial alternating current stimulation on memory performance in healthy adults: A systematic review. [2022]
Working Memory and Transcranial-Alternating Current Stimulation-State of the Art: Findings, Missing, and Challenges. [2023]
Prefrontal oscillatory stimulation modulates access to cognitive control references in retrospective metacognitive commentary. [2018]
The effect of γ-tACS on working memory performance in healthy controls. [2018]
A meta-analysis suggests that tACS improves cognition in healthy, aging, and psychiatric populations. [2023]
A Systematic Review of tACS Effects on Cognitive Functioning in Older Adults Across the Healthy to Dementia Spectrum. [2023]
The Modulation of Cognitive Performance with Transcranial Alternating Current Stimulation: A Systematic Review of Frequency-Specific Effects. [2020]
Neurodynamic correlates for the cross-frequency coupled transcranial alternating current stimulation during working memory performance. [2022]