Trial Outcomes & Findings for Feasibility of Gamma Transcranial Alternating Current Stimulation to Reduce Beta-amyloid Load and Improve Memory (NCT NCT04646499)

Last Updated: 2023-07-27

Results Overview

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.

Recruitment status

COMPLETED

Study phase

Target enrollment

14 participants

Primary outcome timeframe

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

Results posted on

2023-07-27

Participant Flow

Participant milestones

Participant milestones
Measure	Gamma Stimulation Group This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Overall Study STARTED	14
Overall Study COMPLETED	13
Overall Study NOT COMPLETED	1

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

Only data from participants who completed the full protocol were analyzed.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Age, Continuous	74 years STANDARD_DEVIATION 5 • n=5 Participants • Only data from participants who completed the full protocol were analyzed.
Sex: Female, Male Female	6 Participants n=5 Participants • Only data from participants who completed the full protocol were analyzed.
Sex: Female, Male Male	7 Participants n=5 Participants • Only data from participants who completed the full protocol were analyzed.
Ethnicity (NIH/OMB) Hispanic or Latino	0 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Ethnicity (NIH/OMB) Not Hispanic or Latino	13 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) Asian	1 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) Black or African American	1 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) White	11 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) More than one race	0 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Region of Enrollment United States	13 Participants n=5 Participants • One participant was enrolled, but dropped out prior to data collection.
Beta Amyloid	0.06 unitless ratio STANDARD_DEVIATION 0.02 • n=5 Participants • One participant was enrolled, but dropped out prior to data collection. Only data from participants who completed the full protocol were analyzed. Higher values indicate worse outcomes.
Tau	3.38 pg/mL STANDARD_DEVIATION 0.97 • n=5 Participants • One participant was enrolled, but dropped out prior to data collection. Only data from participants who completed the full protocol were analyzed. Higher values indicate worse outcomes.
Memory: Recall	6.54 number of items correctly remembered STANDARD_DEVIATION 4.29 • n=5 Participants • One participant was enrolled, but dropped out prior to data collection. Only data from participants who completed the full protocol were analyzed.
Memory: Paired Associates	60 percentage of items correctly remembered STANDARD_DEVIATION 20 • n=5 Participants • One participant was enrolled, but dropped out prior to data collection. Only data from participants who completed the full protocol were analyzed.
Memory: Fluency	14.67 number of items named STANDARD_DEVIATION 3.78 • n=5 Participants • One participant was enrolled, but dropped out prior to data collection. Only data from participants who completed the full protocol were analyzed. Higher is better. Unit is number of items named that start with the letter f, a, or s.

PRIMARY outcome

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

Population: Only data from participants who completed the full protocol were analyzed.

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Side Effects	0.53 units on a scale Standard Deviation 0.65

PRIMARY outcome

Timeframe: post-tACS, up to 1 month

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

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=14 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Drop Out	1 Participants

SECONDARY outcome

Timeframe: pre-tACS (baseline) and post-tACS (1 month)

Population: Only data from participants who completed the full protocol were analyzed.

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.

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Beta Amyloid Load Change	0.0008 unitless ratio Standard Deviation 0.006

SECONDARY outcome

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

Population: Only data from participants who completed the full protocol were analyzed.

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.

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Memory: Recall Change	1.5 words correct Standard Deviation 2.1

SECONDARY outcome

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

Population: Only data from participants who completed the full protocol were analyzed.

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.

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Memory: Paired Associates Change	11.5 percent correct Standard Deviation 21.0

SECONDARY outcome

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

Population: Only data from participants who completed the full protocol were analyzed.

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.

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Memory: Fluency Change	1.5 number of items named Standard Deviation 2.6

SECONDARY outcome

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

Population: Only data from participants who completed the full protocol were analyzed.

Plasma tau levels was assessed pre and post intervention. Change was calculated as post minus pre. Greater decrease is better.

Outcome measures

Outcome measures
Measure	Gamma Stimulation Group n=13 Participants This group received gamma stimulation Transcranial alternating current stimulation: Transcranial alternating current stimulation (tACS) was applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Change in Tau	0.27 pg/mL Standard Deviation 0.72

Adverse Events

Gamma Stimulation Group

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Dr. Theodore Zanto

University of California San Francisco

Phone: 415-502-7322

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place