Feasibility of Gamma Transcranial Alternating Current Stimulation to Reduce Beta-amyloid Load and Improve Memory

University of California, San Francisco14 enrolled

Overview

This project assessed the feasibility of transcranial alternating current stimulation in the gamma band to lower beta-amyloid load and improve memory performance.

Thirteen individuals with aMCI received eight 60-minute sessions of 40-Hz (gamma) transcranial alternating current stimulation (tACS) in a single-arm design. Outcome measures were assessed pre- and post-intervention.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Mild Cognitive Impairment

Interventions

Transcranial alternating current stimulationDEVICE

Transcranial alternating current stimulation (tACS) will be applied at 40 Hz (gamma band) during eight sessions over the course of a month.

Eligibility

Sex: ALLMin age: 55 YearsMax age: 80 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * English speaking * Grade 12 or more education * Normal or corrected to normal vision and hearing * Ability to complete cognitive tasks * Ability to cooperate and comply with all study procedures * Ability to tolerate tACS * Self-reported memory complaint * Diagnosed with mild cognitive impairment * Amyloid positive Exclusion Criteria: * Neurological or psychiatric disorders other than mild cognitive impairment * Receiving investigational medications or have participated in a trial with investigational medications within last 30 days * Family history of epilepsy * Implanted electronic devices (e.g., pacemaker) * Prior head trauma * Pregnant * IQ \< 80 * Taking cholinesterase inhibitory, memantine, or psychotropic medication * Taking anti-depressants or anti-anxiety medication * Color blind * Substance abuse * Glaucoma * Macular degeneration * Amblyopia (lazy eye) * Strabismus (crossed eyes)

Locations (1)

University of California, San Francisco

San Francisco, California, United States

Outcomes

Primary Outcomes

Side Effects

Side effects were measured on a scale from 0 (not noticable) to 10 (not tolerable): headache, neck pain, scalp pain, tingling, itching, burning sensation, increased sleepiness, trouble concentrating, acute mood change, and phosphenes. Average rating across all measures reported as indicator of side effects.

Time frame: Average of all post-tACS sessions, up to 1 month

Drop Out

Drop out rate will be assessed as the number of participants who withdraw or are withdrawn from the study.

Time frame: post-tACS, up to 1 month

Secondary Outcomes

Beta Amyloid Load Change

Change in plasma-based beta amyloid (AB) load was assessed as the AB42/40 ratio, calculated as post minus pre AB42/40 ratio. Greater increase is better.

Time frame: pre-tACS (baseline) and post-tACS (1 month)

Memory: Recall Change

Episodic memory was assessed pre and post intervention as the number of words correct during the short delay free recall portion of the California Verbal Learning Test. Change was assessed as post minus pre. Greater increase is better.

Time frame: pre-tACS (baseline), post-tACS (after one month of treatment)

Memory: Paired Associates Change

Episodic memory was assessed pre and post intervention from memory accuracy for a paired associates task for visual objects. Change was assessed post minus pre. Greater increase is better.

Time frame: pre-tACS (baseline), post-tACS (after one month of treatment)

Memory: Fluency Change

Episodic memory fluency was assessed pre and post intervention from performance on the FAS task. Unit of measurement is the number of words names starting with the letter f, a, or s. Change was calculated as post minus pre. Greater increase is better.

Data from ClinicalTrials.gov

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