Brain Stimulation for Working Memory

Recruiting in Palo Alto (17 mi)

Overseen by Hamdi Eryilmaz, Ph.D.

Age: 18 - 65

Sex: Any

Travel: May Be Covered

Time Reimbursement: Varies

Trial Phase: Academic

Recruiting

Sponsor: Massachusetts General Hospital

Must not be taking: Psychotropics, Dopamine drugs, Nicotine, others

Disqualifiers: Neurological disorder, Seizures, Pregnancy, others

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. ^{1 2 3 4 5}

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. ^{2 3 6 7 8}

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. ^{1 2 3 5 9}

Research Team

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.

Trial 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 (Device)
• Placebo tACS (Device)

Trial Overview The 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

Group I: Theta-nested gamma tACS applied during passive task epochs Experimental Treatment 1 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 delays Experimental Treatment 1 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 delays Experimental Treatment 1 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 performance Placebo Group 1 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.

Who Is Running the Clinical Trial?

Massachusetts General Hospital

Lead Sponsor

Trials

3,066

Recruited

13,430,000+

Dr. William Curry

Massachusetts General Hospital

Chief Medical Officer

MD from Harvard Medical School

Dr. Anne Klibanski

Massachusetts General Hospital

Chief Executive Officer since 2019

MD from Harvard Medical School

Findings from Research

In a study involving 18 healthy participants, gamma (γ)-tACS showed a selective improvement in working memory performance on a 3-back task compared to tDCS and sham stimulation, suggesting its potential for cognitive enhancement.

The results indicate that γ-tACS may be a more effective method for neuromodulation than traditional tDCS, warranting further investigation into its applications for improving cognitive functions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

The effect of γ-tACS on working memory performance in healthy controls. Hoy, KE., Bailey, N., Arnold, S., et al.[2018]

References

1. United States pubmed.ncbi.nlm.nih.gov

Individually tuned theta HD-tACS improves spatial performance. [2023]

2. Italy pubmed.ncbi.nlm.nih.gov

The effects of transcranial alternating current stimulation on memory performance in healthy adults: A systematic review. [2022]

3. Switzerland pubmed.ncbi.nlm.nih.gov

Working Memory and Transcranial-Alternating Current Stimulation-State of the Art: Findings, Missing, and Challenges. [2023]

4. Netherlands pubmed.ncbi.nlm.nih.gov

Prefrontal oscillatory stimulation modulates access to cognitive control references in retrospective metacognitive commentary. [2018]

5. United States pubmed.ncbi.nlm.nih.gov

The effect of γ-tACS on working memory performance in healthy controls. [2018]

6. United States pubmed.ncbi.nlm.nih.gov

A meta-analysis suggests that tACS improves cognition in healthy, aging, and psychiatric populations. [2023]

7. United States pubmed.ncbi.nlm.nih.gov

A Systematic Review of tACS Effects on Cognitive Functioning in Older Adults Across the Healthy to Dementia Spectrum. [2023]

8. Switzerland pubmed.ncbi.nlm.nih.gov

The Modulation of Cognitive Performance with Transcranial Alternating Current Stimulation: A Systematic Review of Frequency-Specific Effects. [2020]

9. Switzerland pubmed.ncbi.nlm.nih.gov

Neurodynamic correlates for the cross-frequency coupled transcranial alternating current stimulation during working memory performance. [2022]