Brain Stimulation for Improving Working Memory

(TravelingTES Trial)

Overseen By Alexander Opitz, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: University of Minnesota

Disqualifiers: Neurological disorder, Metal implant, Head injuries, Chronic condition, Pregnancy, Addiction

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

Compensation: Varies

Number of Visits: 2

Duration: 20 minutes per session

30 Participants Needed

Trial Summary

What is the purpose of this trial?

This trial will test if applying weak electrical currents to the scalp can improve memory in adults by creating moving waves in brain activity. The technique has been studied for its potential to enhance memory and other cognitive functions.

Do I have to stop taking my current medications?

Yes, you must stop taking your current medications because the trial excludes anyone with a medical condition that requires ongoing pharmacological treatment.

Will I have to stop taking my current medications?

Yes, you will need to stop taking your current medications, as the trial excludes anyone with a medical condition that requires ongoing treatment with drugs.

What data supports the idea that Brain Stimulation for Improving Working Memory is an effective treatment?

The available research shows mixed results for the effectiveness of Brain Stimulation for Improving Working Memory. One study found that theta tACS improved spatial performance, suggesting it can help with certain types of memory tasks. Another study compared tACS to another method called TDCS and found that tACS led to better improvements in working memory tasks. However, a systematic review found only small-to-medium effects of tACS on memory performance overall. This suggests that while tACS might help improve working memory, its effects can vary and are not always strong. ^{1 2 3 4 5}

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 performance, particularly when using specific frequencies like theta-tACS. This indicates potential for tACS to enhance working memory, although more research is needed to optimize its application. ^{1 2 3 4 5}

What safety data exists for transcranial alternating current stimulation (tACS)?

The safety data for tACS indicates that most adverse effects are mild and temporary, with no persistent adverse events reported. However, there are fewer safety reports for tACS compared to tDCS. A study on temporal interference tACS (TI-tACS) found no significant neurological or neuropsychological differences between active and sham groups, and no serious adverse effects were observed, suggesting it is safe and tolerable under typical conditions. ^{2 6 7 8 9}

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

tACS is generally considered safe for humans, with most reported side effects being mild and temporary. However, there are fewer safety studies on tACS compared to similar techniques, so ongoing research is needed to fully establish its safety. ^{2 6 7 8 9}

Is Transcranial Alternating Current Stimulation (tACS) a promising treatment for improving working memory?

Yes, Transcranial Alternating Current Stimulation (tACS) is a promising treatment for improving working memory. It is a non-invasive method that can enhance cognitive performance, especially in older adults and those with cognitive deficits. Studies have shown that tACS can improve working memory capacity and is considered safe, cost-effective, and portable. ^{1 2 3 10 11}

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

Transcranial Alternating Current Stimulation (tACS) is unique because it uses non-invasive electrical currents to specifically target brain oscillations, like theta and gamma waves, which are important for 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. ^{1 2 3 10 11}

Research Team

Ivan Alekseichuk, PhD

Principal Investigator

University of Minnesota

Eligibility Criteria

This trial is for adults aged 18-45 with a good grasp of English. It's not suitable for those with chronic neurological or mental disorders, head injuries causing unconsciousness, ongoing medical conditions needing drugs, pregnant or breastfeeding individuals, substance addicts, or people with metal/electric implants in the upper body.

Inclusion Criteria

Confident level of English language

I am between 18 and 45 years old.

Exclusion Criteria

Pregnancy or breast-feeding

History or evidence of chronic neurological or mental disorder

Alcohol or drug addiction

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive transcranial alternating current stimulation (tACS) to assess its impact on working memory performance

20 minutes per session

1 visit (in-person)

Follow-up

Participants are monitored for changes in EEG connectivity and reaction time post-stimulation

5 minutes

1 visit (in-person)

Treatment Details

Interventions

• Transcranial Alternating Current Stimulation (tACS)

Trial Overview The study is testing how traveling-wave transcranial electric stimulation (tACS), a non-invasive brain stimulation technique, affects working memory performance in healthy adults.

Participant Groups

Group I: Parietofrontal Slow Theta Stimulation Experimental Treatment 1 Intervention

Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.

Group II: Parietofrontal Fast Theta Stimulation Experimental Treatment 1 Intervention

Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces parietal-to-frontal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.

Group III: Frontoparietal Slow Theta Stimulation Experimental Treatment 1 Intervention

Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 4 Hz with the intensity of up to 2 mA and duration up to 20 min.

Group IV: Frontoparietal Fast Theta Stimulation Experimental Treatment 1 Intervention

Participants will receive multi-electrode transcranial alternating current stimulation over the prefrontal and parietal brain regions that induces frontal-to-parietal traveling wave at the frequency of 7 Hz with the intensity of up to 2 mA and duration up to 20 min.

Who Is Running the Clinical Trial?

University of Minnesota

Lead Sponsor

Trials

1,459

Recruited

1,623,000+

Brain & Behavior Research Foundation

Collaborator

Trials

63

Recruited

2,900+

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.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

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

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]

In a study involving 30 participants, transcranial alternating current stimulation (TACS) at 6 Hz was found to significantly improve working memory performance compared to transcranial direct current stimulation (TDCS), suggesting TACS may be more effective for enhancing cognitive function.

Despite the overall improvements in reaction times due to practice effects, the results indicate that TACS could be a promising method for optimizing working memory performance, warranting further research into its application.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Modulation of Working Memory Using Transcranial Electrical Stimulation: A Direct Comparison Between TACS and TDCS. Röhner, F., Breitling, C., Rufener, KS., et al.[2020]

In a study involving 20 participants with mild cognitive impairment due to Alzheimer's disease, γ-tACS significantly improved memory performance, as shown by increased scores on the Rey auditory verbal learning test and face-name associations, compared to sham stimulation.

The γ-tACS also enhanced cholinergic transmission, indicated by increased short latency afferent inhibition measured with TMS, suggesting a potential mechanism for its memory-enhancing effects.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Exposure to gamma tACS in Alzheimer's disease: A randomized, double-blind, sham-controlled, crossover, pilot study. Benussi, A., Cantoni, V., Cotelli, MS., et al.[2021]

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 beta frequency (20 Hz) significantly improved the forward digit span memory in young adults, indicating a potential method to enhance short-term memory capacity.

The study found that the benefits of beta-tACS were age-dependent, with younger individuals showing greater improvements compared to midlife adults, suggesting that this technique may be more effective in enhancing memory in younger populations.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Frequency-specific insight into short-term memory capacity. Feurra, M., Galli, G., Pavone, EF., et al.[2018]

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]

Transcranial direct current stimulation (tDCS) is generally considered safe, with most adverse effects being mild and temporary; however, some cases of persistent skin lesions and rare instances of mania or hypomania have been reported, particularly in patients with depression.

Transcranial alternating current stimulation (tACS) has fewer reported adverse events, and no persistent effects have been documented, but more research is needed to fully establish its safety compared to tDCS.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Adverse events of tDCS and tACS: A review. Matsumoto, H., Ugawa, Y.[2020]

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]

In a study with 20 healthy participants, high gamma-band transcranial alternating current stimulation (tACS) at 80 Hz significantly improved working memory capacity, while low gamma tACS at 40 Hz did not show a significant effect.

This research is the first to demonstrate that high gamma tACS can enhance working memory across both visual hemifields, suggesting its potential as a neurorehabilitation method to improve cognitive functions by facilitating communication between brain regions.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

80 Hz but not 40 Hz, transcranial alternating current stimulation of 80 Hz over right intraparietal sulcus increases visuospatial working memory capacity. Park, J., Lee, C., Lee, S., 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]

References

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

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

2. France pubmed.ncbi.nlm.nih.gov

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

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

Modulation of Working Memory Using Transcranial Electrical Stimulation: A Direct Comparison Between TACS and TDCS. [2020]

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

Exposure to gamma tACS in Alzheimer's disease: A randomized, double-blind, sham-controlled, crossover, pilot study. [2021]

5. Italy pubmed.ncbi.nlm.nih.gov

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

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

Frequency-specific insight into short-term memory capacity. [2018]

7. England pubmed.ncbi.nlm.nih.gov

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

8. Netherlands pubmed.ncbi.nlm.nih.gov

Adverse events of tDCS and tACS: A review. [2020]

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

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

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

80 Hz but not 40 Hz, transcranial alternating current stimulation of 80 Hz over right intraparietal sulcus increases visuospatial working memory capacity. [2022]

11. Switzerland pubmed.ncbi.nlm.nih.gov

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