Non-Invasive Brain Stimulation for Working Memory Improvement

Overseen By Ivan Alekseichuk, PhD

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of Minnesota

Disqualifiers: Diminished capacity to consent

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: Unknown

Duration: Immediate effect during stimulation

16 Participants Needed

Trial Summary

What is the purpose of this trial?

This project will assess the feasibility of traveling wave transcranial alternating current stimulation (tACS) to modify working memory performance and large-scale brain connectivity in surgical epilepsy patients.

Do I need to stop taking my current medications for this trial?

The trial information does not specify whether you need to stop taking your current medications.

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

Research shows that Transcranial Alternating Current Stimulation (tACS) has a small-to-medium effect on improving working memory and long-term memory in healthy adults, with specific frequencies like posterior theta-tACS being particularly effective for working memory. ^{1 2 3 4 5}

Is non-invasive brain stimulation, like transcranial alternating current stimulation, safe for humans?

Non-invasive brain stimulation techniques, including transcranial alternating current stimulation (tACS), are generally considered safe for humans. Studies have shown no serious adverse effects in thousands of sessions, with only mild effects like headaches or skin sensations reported occasionally. ^{6 7 8 9 10}

How does Transcranial Alternating Current Stimulation (tACS) differ from other treatments for working memory improvement?

Transcranial Alternating Current Stimulation (tACS) is unique because it uses non-invasive electrical currents to modulate brain activity by matching the frequency of brain oscillations, which can enhance working memory. Compared to other treatments like repetitive transcranial magnetic stimulation (rTMS), tACS is more cost-effective, portable, and has a better safety profile, making it a promising tool for cognitive enhancement, especially in older adults and those with cognitive deficits. ^{2 3 4 5 11}

Research Team

Alexander Opitz, PhD

Principal Investigator

University of Minnesota

Eligibility Criteria

This trial is for adults over 18 who can give their own consent and are undergoing phase II epilepsy surgical evaluation with implanted electrodes. It's not suitable for those unable to consent.

Inclusion Criteria

The patient can consent for themselves

I have or will have electrodes implanted for epilepsy surgery evaluation.

I am 18 years old or older.

Exclusion Criteria

I have difficulty understanding and making health decisions.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive traveling wave transcranial alternating current stimulation to modify working memory performance and brain connectivity

Immediate effect during stimulation

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Treatment Details

Interventions

• Transcranial Alternating Current Stimulation

Trial Overview The study tests if a non-invasive brain stimulation technique, called traveling wave transcranial alternating current stimulation (tACS), can improve working memory and alter brain connectivity in epilepsy patients.

Participant Groups

Group I: Stimulation Theta Group Experimental Treatment 1 Intervention

Participants will experience traveling wave transcranial alternating current stimulation over the fronto-parietal regions at 4 Hz (theta condition).

Group II: Stimulation Beta Group Experimental Treatment 1 Intervention

Participants will experience traveling wave transcranial alternating current stimulation over the fronto-parietal regions at 23 Hz (beta condition).

Who Is Running the Clinical Trial?

University of Minnesota

Lead Sponsor

Trials

1,459

Recruited

1,623,000+

National Institute of Mental Health (NIMH)

Collaborator

Trials

3,007

Recruited

2,852,000+

Findings from Research

In a randomized crossover study involving 43 participants (22 with major depression and 21 healthy volunteers), gamma transcranial alternating current stimulation (tACS) did not improve working memory performance during a computerized task, regardless of whether the stimulation was active or sham.

The study highlights the need for standardized methodologies in gamma tACS research, as the lack of cognitive improvement aligns with previous inconsistent findings in the field.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Single session gamma transcranial alternating stimulation does not modulate working memory in depressed patients and healthy controls. Palm, U., Baumgartner, C., Hoffmann, L., 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.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Working Memory and Transcranial-Alternating Current Stimulation-State of the Art: Findings, Missing, and Challenges. Al Qasem, W., Abubaker, M., Kvašňák, E.[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.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

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) 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.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Individually tuned theta HD-tACS improves spatial performance. Zhang, DW., Moraidis, A., Klingberg, T.[2023]

The study found that online repetitive transcranial magnetic stimulation (rTMS) applied to the left dorsolateral prefrontal cortex significantly improved memory recall accuracy in both young and older adults, particularly during the most challenging cognitive tasks.

This suggests that rTMS could be a promising method for enhancing working memory manipulation, especially in high-demand situations, warranting further research into its potential benefits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Online repetitive transcranial magnetic stimulation during working memory in younger and older adults: A randomized within-subject comparison. Beynel, L., Davis, SW., Crowell, CA., et al.[2022]

Low intensity transcranial electrical stimulation (TES) is considered safe, with no serious adverse events reported in over 18,000 sessions across various populations, including healthy individuals and patients with neurological or psychiatric conditions.

While moderate adverse events like skin burns from tDCS are rare, mild adverse events such as headaches and fatigue are more common, and the safety profile is consistent across different age groups and vulnerable populations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. Antal, A., Alekseichuk, I., Bikson, M., et al.[2023]

In a study involving 38 healthy adults, temporal interference transcranial alternating current stimulation (TI-tACS) was found to be safe, with no significant adverse effects reported after active stimulation at 2 mA for 30 minutes.

The study showed no significant differences in neurological and neuropsychological measurements between the active TI-tACS group and the sham group, indicating that TI-tACS does not negatively impact brain function under the tested conditions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety Evaluation of Employing Temporal Interference Transcranial Alternating Current Stimulation in Human Studies. Piao, Y., Ma, R., Weng, Y., et al.[2022]

Transcranial alternating current stimulation (tACS) has been shown to lead to modest to moderate improvements in cognitive function across various domains, including working memory and attention, based on a systematic review of 102 studies involving 2893 participants.

The most significant cognitive improvements were observed after tACS treatment (offline effects) rather than during the stimulation (online effects), and studies that optimized stimulation based on current flow models yielded better outcomes.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

A meta-analysis suggests that tACS improves cognition in healthy, aging, and psychiatric populations. Grover, S., Fayzullina, R., Bullard, BM., et al.[2023]

Transcranial Direct Current Stimulation (tDCS) has been shown to be safe, with no reports of Serious Adverse Effects or irreversible injuries across over 33,200 sessions involving more than 1,000 subjects, including vulnerable populations.

Safety assessments indicate that the current densities used in conventional tDCS (≤4 milliamperes) are significantly lower than those that could potentially cause brain injury, suggesting that tDCS protocols are well within safe limits.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016. Bikson, M., Grossman, P., Thomas, C., et al.[2022]

Transcranial alternating current stimulation (tACS) is a promising non-invasive technique that may help improve cognitive deficits by targeting and enhancing cortical network synchronization.

Current research suggests that tACS could clarify the causal relationship between specific brain activity patterns and cognitive abilities, paving the way for new treatment options for cognitive impairments in psychiatric illnesses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Targeting the neurophysiology of cognitive systems with transcranial alternating current stimulation. Fröhlich, F., Sellers, KK., Cordle, AL.[2018]

Frequency-tuned noninvasive brain stimulation can effectively modulate brain oscillations, which are linked to working memory, leading to changes in behavior and cognitive functions.

This technique has advanced our understanding of how brain oscillations influence memory and has potential therapeutic applications for enhancing cognitive abilities.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Driving working memory with frequency-tuned noninvasive brain stimulation. Albouy, P., Baillet, S., Zatorre, RJ.[2019]

References

1. France pubmed.ncbi.nlm.nih.gov

Single session gamma transcranial alternating stimulation does not modulate working memory in depressed patients and healthy controls. [2022]

2. Switzerland pubmed.ncbi.nlm.nih.gov

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

3. Italy pubmed.ncbi.nlm.nih.gov

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

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

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

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

Online repetitive transcranial magnetic stimulation during working memory in younger and older adults: A randomized within-subject comparison. [2022]

6. Netherlands pubmed.ncbi.nlm.nih.gov

Low intensity transcranial electric stimulation: Safety, ethical, legal regulatory and application guidelines. [2023]

7. Switzerland pubmed.ncbi.nlm.nih.gov

Safety Evaluation of Employing Temporal Interference Transcranial Alternating Current Stimulation in Human Studies. [2022]

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

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

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

Safety of Transcranial Direct Current Stimulation: Evidence Based Update 2016. [2022]

10. England pubmed.ncbi.nlm.nih.gov

Targeting the neurophysiology of cognitive systems with transcranial alternating current stimulation. [2018]

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

Driving working memory with frequency-tuned noninvasive brain stimulation. [2019]