Clinical trial NCT05907707: Effects of Gamma-tACS on Memory and Sleep
Official title: Effects of Transcranial Alternating Current Stimulation (tACS) at Gamma Band Frequencies on Memory Recall and Sleep in Healthy Elderly Participants
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Transcranial Alternating Current Stimulation
Aging
Cognitive Decline
Memory
Sleep
Lead sponsor: University of North Carolina, Chapel Hill
Sponsor class: OTHER
First posted: 2023-06-18
Enrollment: 11
Sex: ALL
Minimum age (years): 50
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: OTHER

Brief 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. 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.


Eligibility criteria: Inclusion Criteria:

* \>50 years old

Exclusion Criteria:

* 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)
* 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

Primary outcomes:
measure: Percent of Participants Tolerating Cognitive Testing During tACS
timeFrame: Baseline (Day 1)
measure: Verbal Memory at Day 1
timeFrame: Baseline (Day 1)
measure: Verbal Memory at Day 2
timeFrame: Follow-Up (Day 2)
measure: Verbal Memory at Day 5
timeFrame: Follow-Up (Day 5)
measure: Associative Verbal Memory at Day 1
timeFrame: Baseline (Day 1)
measure: Associative Verbal Memory at Day 2
timeFrame: Follow-Up (Day 2)
measure: Associative Verbal Memory at Day 5
timeFrame: Follow-Up (Day 5)
measure: Percentage of Participants in Which it is Possible to Obtain at Least 4 Hours EEG Recording
timeFrame: Baseline (Day 1)
measure: Percentage of Participants Who Wear the EEG Device During All Three Nights for at Least 4 Hours
timeFrame: Baseline (Day 1)
measure: Amount of Sleep Spindles in Sleep-EEG
timeFrame: Baseline (Day 1)
measure: Amount of Slow Wave Sleep in Sleep-EEG
timeFrame: Baseline (Day 1)
Secondary outcomes:
measure: Performance in Phonematic Fluency-Correct Words
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
measure: Performance in Phonematic Fluency-Perseverations
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
measure: Performance in Phonematic Fluency-Rule Breaks
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
measure: Executive Functioning (Time to Complete Stroop Test)
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
measure: Executive Functioning (Trail Making Test)
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
measure: Attentional Performance (TAP)
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
Other outcomes:
measure: Exploration of a Relationship (Correlation) Between the Amount of Sleep Spindles and Slow Wave Sleep With Recall
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
measure: Exploration of a Relationship (Correlation) of Sleep-Wake-Schedule Changes and Type of Stimulation
timeFrame: Baseline (Day 1), Follow-Up (Day 2)
Locations:
city: Chapel Hill
country: United States
facility: Carolina Center for Neurostimulation
state: North Carolina
Study officials:
affiliation: University of North Carolina, Chapel Hill
name: Flavio Frohlich, PhD
role: PRINCIPAL_INVESTIGATOR
References: