40 Hz Transcranial Alternating Current Stimulation for Inducing Gamma Oscillations

Not Applicable

Recruiting

• Conditions: Alzheimer Disease; Cognitive Decline

• Registration Number: NCT06740864
• Lead Sponsor: The National Brain Mapping Laboratory (NBML)

Brief Summary

This study aims to compare the efficacy of different 40 Hz tACS protocols in entraining gamma oscillations, which are linked to various cognitive functions and play a significant role in cognitive impairments like Alzheimer's disease. Specifically, it examines the effects of 40 Hz tACS applied to frontal brain regions versus fronto-temporal regions on gamma oscillations and working memory in healthy elderly individuals.

Detailed Description

Not available

Study Timeline

• Study Start: 2024-06-01
• Status Verified: 2024-12
• Study First Submitted: 2024-12-14
• Study First Submitted QC: 2024-12-14
• Study First Posted: 2024-12-18
• Last Update Submitted: 2024-12-24
• Last Update Posted: 2024-12-27
• Primary Completion: 2025-02-01
• Study Completion: 2025-06-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• healthy elderly between 50-80 years of age
• normal or corrected to normal eye vision
• right-handed
• non-smokers
• at least 70 % accuracy in working memory training task

Exclusion Criteria

• history of neurological or psychiatric disorders including seizures or epilepsy,
• Taking CNS, blood pressure and other medications
• having metal implants in the head and neck
• significant cognitive decline meassured by The Montreal Cognitive Assessment (MoCA)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Primary Outcome Measures

Name	Time	Method
Working Memory behavioral performance	During procedure (20 minutes)	Participants view a continuous sequence of alphabet letters, presented as stimuli in Arial font, size 120pt, on a tube screen positioned at 60cm eye distance. The stimuli are shown with a time interval of two seconds between them. The task consisted of six blocks with 70 stimuli, including 12 possible hit trials. Participants were instructed to press the left key on a response box if the presented stimulus matched either the one presented one trial prior (1-Back) or three trials prior (3-Back). In all other cases, participants press the right key. The left button is pressed with the index finger, while the right button is pressed with the middle finger of the right hand, with buttons aligned horizontally. The response condition varied by block, with three blocks for 3-Back and three for 1-Back, and the order was counterbalanced across participants and sessions.
electroencephalogram (EEG) oscillatory power	up to 2 hours after the intervention	Change in the EEG power in the gamma band
electroencephalogram (EEG) functional connectivity	up to 2 hours after the intervention	Change in EEG functional connectivity, specifically global efficiency, coherence, and phase-locking value at gamma frequency

Secondary Outcome Measures

Name	Time	Method
electroencephalogram (EEG) oscillatory power	up to 2 hours after the intervention	Change in the EEG power in alpha, delta, theta and beta bands

Trial Locations

Locations (1)

Institute for Research in Fundamental Sciences; 🇮🇷 Tehran, Iran, Islamic Republic of