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Transcranial Alternating Current StimulationNCT05907707

Effects of Gamma-tACS on Memory and Sleep

A study testing Gamma transcranial alternating current stimulation, EEG headband and Actigraphy wristband in people with Transcranial Alternating Current Stimulation and Aging, run by University of North Carolina, Chapel Hill at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record
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Trial summary

The purpose of this clinical trial is to investigate the feasibility and efficacy of non-invasive transcranial alternating current stimulation (tACS) at gamma frequency in enhancing memory recall and modulating sleep network dynamics measured by at-home electroencephalography (EEG) in healthy elderly people. Read more about this study

Who is it for?
Ages 50 years and olderHealthy volunteers can take part
What is being tested?
Gamma transcranial alternating current stimulation, EEG headband and Actigraphy wristband
Type of treatment
Medical device
Could I receive a placebo?
No, everyone receives an active treatment
How many people
11 participants
Where
1 siteUnited States
Study dates
28 Jun 2023to 28 Dec 2023
Phase
Interventional
Are there results?
Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 50 years and older
  • All sexes
  • Healthy volunteers accepted
  • Adult, Older adult

Who may be able to join

  • >50 years old

Who cannot join

  • Implanted device or metal in head (including cochlear implant or other hearing aid), cardiac pacemaker or any other powered medical device
  • Known neurological disease from history (epilepsy, sleep disorder (insomnia, sleep apnea, restless legs syndrome, parasomnia), stroke or transitory ischemic attack, cognitive impairment, neurodegenerative disease (for example Alzheimer's disease, Parkinson's disease or amyotrophic lateral sclerosis), immune-mediated disease of the central nervous system, chronic infectious brain disease, brain tumor, traumatic brain injury with loss of consciousness and/or intracranial bleeding, chronic pain with the need for daily analgesic use)
  • Positive screening for epilepsy (questionnaire)
  • Pathological Montreal Cognitive Assessment (MoCA <26/30 points)
  • Brain surgery in the past (lifetime)
  • Known psychiatric disorder from history (schizophrenia (lifetime), obsessive compulsive disorder (OCD; lifetime), borderline personality disorder (lifetime), anxiety disorder (lifetime), bipolar disorder (lifetime), psychosis (lifetime), eating disorder (lifetime), depression (within the last three months)
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  • Positive screening for anxiety disorder (GAD-7 ≥10/21 points) or positive screening for depression (PHQ-9 ≥5/27 points)
  • Known other relevant medical condition from history (moderate to severe chronic obstructive pulmonary disease (COPD), abnormal kidney function (defined as estimated Glomerular Filtration Rate <60ml/min), current liver disease (defined as hepatitis and/or liver cirrhosis), cancer, diabetes mellitus, cardiac disease (heart failure, myocardial infarct, atrial fibrillation and revascularization - all within the last three months)
  • Working in night shifts or going to bed after midnight on 3 or more nights per week
  • Positive screening for sleep disorder (PSQI >5/21 points)
  • Psychotropic treatment or illegal drugs (including cannabis) within the last three months
  • Indication for alcohol use disorder: AUDIT score (Alcohol Use Disorders Identification Test; screening for unhealthy alcohol use) ≥7 for females and for males ≥ 65 years or ≥8 for males <65 years
  • Not willing to abstain alcohol at least 24 hours before each study visit
  • Pregnancy, planned pregnancy, fertility treatment planned or ongoing
  • Having experienced an adverse event in the past after receiving Transcranial Magnetic Stimulation (TMS)
  • If, after filling out a questionnaire on the participant's medical history that informs researchers of relevant events that marginally increase the risk of an adverse event occurring during TMS, researchers will exercise their expert judgement to determine whether that participant should be excluded

Trial locations and contacts

1 site in 1 country.

United States1 site

  • Carolina Center for Neurostimulation

    Chapel Hill, North Carolina, 27516

Other trials in United States

About this study

Official title: Effects of Transcranial Alternating Current Stimulation (tACS) at Gamma Band Frequencies on Memory Recall and Sleep in Healthy Elderly Participants

The purpose of this clinical trial is to investigate the feasibility and efficacy of non-invasive transcranial alternating current stimulation (tACS) at gamma frequency in enhancing memory recall and modulating sleep network dynamics measured by at-home electroencephalography (EEG) in healthy elderly people. Eligible participants will first collect sleep EEG at home for one night to acclimate to the data collection during sleep. Participants are then randomized into first undergoing either tACS at gamma band frequencies (i.e. 40Hz) or tACS at a control frequency (i.e. 21Hz). Stimulation is administered in the lab during a cognitive testing battery that includes memorizing items. After a night of sleep with EEG at home, participants return to the lab the following day to measure memory recall. Recall is performed again after five days. This sequence of encoding during stimulation in the lab, sleep EEG at home for one night, and recall is then repeated for the other stimulation condition about a week later. Participants are wearing an actigraphy wristband throughout the study period.

Being tested
Gamma transcranial alternating current stimulation, Control transcranial alternating current stimulation, EEG headband, Actigraphy wristband
Medical subject headings
Cognitive Dysfunction

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • Gamma transcranial alternating current stimulationDevice

    Also called DC-STIMULATOR MC Stimulator Plus

    tACS (gamma frequency, 40Hz) during cognitive testing (about 40 minutes duration).

  • Control transcranial alternating current stimulationDevice

    Also called DC-STIMULATOR MC Stimulator Plus

    tACS (control frequency, 21Hz) during cognitive testing (about 40 minutes duration).

  • EEG headbandDevice

    Also called ULTEEMNite

    At-home, ambulatory, single-channel EEG headband which records brain activity during sleep

  • Actigraphy wristbandDevice

    At-home, ambulatory, wrist-worn accelerometer which records levels of motor activity during the whole day

Study groups in NCT05907707
Study groupRoleWhat they receive
First gamma (40Hz) stimulation, then active control (21Hz) stimulationExperimentalAfter collecting sleep EEG at home for one night to acclimate to the data collection during sleep, participants first receive gamma (40Hz) tACS on Day 1 followed by a 5-9 day washout. Participants then receive active control (21Hz) stimulation.
Receives: Device: Gamma transcranial alternating current stimulation; Device: Control transcranial alternating current stimulation; Device: EEG headband; Device: Actigraphy wristband
First active control (21 Hz) stimulation, then gamma (40 Hz) stimulationExperimentalAfter collecting sleep EEG at home for one night to acclimate to the data collection during sleep, participants first receive active control (21Hz) tACS on Day 1 followed by a 5-9 day washout. Participants then receive gamma (40Hz) stimulation.
Receives: Device: Gamma transcranial alternating current stimulation; Device: Control transcranial alternating current stimulation; Device: EEG headband; Device: Actigraphy wristband

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Percent of Participants Tolerating Cognitive Testing During tACS

    To establish acceptability of tACS combined with cognitive testing in healthy elderly participants and will be considered acceptable if at least >/= 80% of participants tolerate the procedure.

    Measured: Baseline (Day 1)

  2. Verbal Memory at Day 1

    Participants will memorize 15 words ("Rey Auditory Verbal Learning Test") during gamma-tACS or control-tACS. They will be required to recall the words on the same day. The number of correctly remembered words will be recorded.

    Measured: Baseline (Day 1)

  3. Verbal Memory at Day 2

    Participants will memorize 15 words ("Rey Auditory Verbal Learning Test") during gamma-tACS or control-tACS. They will be required to recall the words on the day after. The number of correctly remembered words will be recorded.

    Measured: Follow-Up (Day 2)

  4. Verbal Memory at Day 5

    Participants will memorize 15 words ("Rey Auditory Verbal Learning Test") during gamma-tACS or control-tACS. They will be required to recall the words after 5 days. The number of correctly remembered words will be recorded.

    Measured: Follow-Up (Day 5)

  5. Associative Verbal Memory at Day 1

    Participants will memorize 8 word-pairs during gamma-tACS or control-tACS. They will be required to recall the pairs on the same day. The number of correctly remembered word pairs will be recorded.

    Measured: Baseline (Day 1)

  6. Associative Verbal Memory at Day 2

    Participants will memorize 8 word-pairs during gamma-tACS or control-tACS. They will be required to recall the pairs on the day after. The number of correctly remembered word pairs will be recorded.

    Measured: Follow-Up (Day 2)

  7. Associative Verbal Memory at Day 5

    Participants will memorize 8 word-pairs during gamma-tACS or control-tACS. They will be required to recall the pairs after 5 days. The number of correctly remembered word pairs will be recorded.

    Measured: Follow-Up (Day 5)

  8. Percentage of Participants in Which it is Possible to Obtain at Least 4 Hours EEG Recording

    To establish feasibility of at-home use of a single-channel EEG device during sleep. This will be considered feasible if the device has been worn for at least 4 hours during the first night for >/= 80% of participants.

    Measured: Baseline (Day 1)

  9. Percentage of Participants Who Wear the EEG Device During All Three Nights for at Least 4 Hours

    To establish acceptability of at-home use of the single-channel EEG device during multiple nights. Acceptability will be considered as given if the device has been worn for at least 4 hours during each of the three nights in >/=80% of participants.

    Measured: Baseline (Day 1)

  10. Amount of Sleep Spindles in Sleep-EEG

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on the number of sleep spindles occuring during the night after the intervention. Sleep spindles during the first two hours of sleep-EEG will be counted. A sleep spindle is defined as a train of sinusoidal waves with frequency 11-16 Hz and a duration of at least 0.5 seconds.

    Measured: Baseline (Day 1)

  11. Amount of Slow Wave Sleep in Sleep-EEG

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on the amount of slow wave sleep (deep/delta sleep) occuring during the night after the intervention. The amount of slow wave sleep during the first two hours of sleep-EEG will be counted.

    Measured: Baseline (Day 1)

Secondary outcomes (6)

  1. Performance in Phonematic Fluency-Correct Words

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on a phonematic fluency-task during 1 minute. The number of correct words will be calculated.

    Measured: Baseline (Day 1), Follow-Up (Day 2)

  2. Performance in Phonematic Fluency-Perseverations

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on a phonematic fluency-task (i.e. production of words that start with a specific letter) during 1 minute. Number of correct words, number of perseverations and number of rule breaks will be calculated.

    Measured: Baseline (Day 1), Follow-Up (Day 2)

  3. Performance in Phonematic Fluency-Rule Breaks

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on a phonematic fluency-task during 1 minute. Number of correct words, number of perseverations and number of rule breaks will be calculated.

    Measured: Baseline (Day 1), Follow-Up (Day 2)

  4. Executive Functioning (Time to Complete Stroop Test)

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on the Stroop Color and Word Test during and on the day after the intervention. Time for test completion and errors will be calculated. Selective attention was evaluated with the Stroop Color Word Interference Test. In the interference portion of this test, the subject identifies the color of ink in which words ("red", "green", or "blue") are printed, requiring the subject to inhibit their natural tendency to read the word. A subject's score is the time taken to identify 50 stimulus items. The time taken to complete the maze is inversely proportional to the cognitive function.

    Measured: Baseline (Day 1), Follow-Up (Day 2)

  5. Executive Functioning (Trail Making Test)

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on the Trail Making Test (TMT; connecting a set of numbers and numbers and letters as quickly as possible while maintaining accuracy) during and on the day after the intervention. The TMT (Part A and Part B) is a measure of visuomotor processing/sequencing speed. Participants must draw a line connecting numbers in ascending order as quickly as possible. Completion time in seconds is recorded (0-120, where lower scores represent better performance). Completion time of Part B is divided by completion time of Part A (Ratio B/A).

    Measured: Baseline (Day 1), Follow-Up (Day 2)

  6. Attentional Performance (TAP)

    To investigate the effect of a single session of gamma-tACS (compared to control-tACS) on subtests of the Test of Attentional Performance (TAP) during and on the day after the intervention. Percentile ranks for the following subtests will be calculated: Alertness (reaction time under two conditions), Go/NoGo (stimuli that require a selective reaction, that is, to react or not to react), Divided Attention (a visual and an auditory task must be processed in parallel), Visual Scanning (a matrix-like arrangement of 5 x 5 stimuli is used, the aim being to detect whether this arrangement includes a critical stimulus or not).

    Measured: Baseline (Day 1), Follow-Up (Day 2)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted18 Jun 2023
  2. Study start28 Jun 2023
  3. Primary completion28 Dec 2023
  4. Study completion28 Dec 2023

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase N/A
Primary purpose
Other
Allocation
Randomised
Intervention model
Crossover
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
11 participants (actual)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05907707
Sponsor's protocol ID
23-0597
Status last verified
Nov 2024
First submitted
18 May 2023
Last updated
2 Apr 2025
FDA-regulated drug
No
FDA-regulated device
Yes
Individual data sharing
No

Questions about this trial

What is this clinical trial studying?

A study testing Gamma transcranial alternating current stimulation, EEG headband and Actigraphy wristband in people with Transcranial Alternating Current Stimulation and Aging, run by University of North Carolina, Chapel Hill at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 1 inclusion and 16 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 2 Apr 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 18 Dec 2024). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Percent of Participants Tolerating Cognitive Testing During tACS (time frame: Baseline (Day 1)). The study lists 11 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05907707.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 2 Apr 2025; AzTrials last refreshed its copy on 6 Nov 2026.

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