Mild Cognitive Impairment
Conditions
Brief summary
This project assessed the feasibility of transcranial alternating current stimulation in the gamma band to lower beta-amyloid load and improve memory performance.
Detailed description
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.
Interventions
DEVICETranscranial alternating current stimulation
Transcranial alternating current stimulation (tACS) will be applied at 40 Hz (gamma band) during eight sessions over the course of a month.
Sponsors
National Institute on Aging (NIA)
University of California, San Francisco
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
55 Years to 80 Years
Healthy volunteers
Yes
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)
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Side Effects | Average of all post-tACS sessions, up to 1 month | 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. |
| Drop Out | post-tACS, up to 1 month | Drop out rate will be assessed as the number of participants who withdraw or are withdrawn from the study. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Memory: Recall Change | pre-tACS (baseline), post-tACS (after one month of treatment) | 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. |
| Memory: Fluency Change | pre-tACS (baseline), post-tACS (after one month of treatment) | 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. |
| Change in Tau | pre-tACS (baseline), post-tACS (after one month of treatment) | Plasma tau levels was assessed pre and post intervention. Change was calculated as post minus pre. Greater decrease is better. |
| Memory: Paired Associates Change | pre-tACS (baseline), post-tACS (after one month of treatment) | 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. |
| Beta Amyloid Load Change | pre-tACS (baseline) and post-tACS (1 month) | 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. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| 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. | 13 |
| Total | 13 |
Baseline characteristics
| Characteristic | Gamma Stimulation Group |
|---|---|
| Age, Continuous | 74 years STANDARD_DEVIATION 5 |
| Beta Amyloid | 0.06 unitless ratio STANDARD_DEVIATION 0.02 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 0 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 13 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Memory: Fluency | 14.67 number of items named STANDARD_DEVIATION 3.78 |
| Memory: Paired Associates | 60 percentage of items correctly remembered STANDARD_DEVIATION 20 |
| Memory: Recall | 6.54 number of items correctly remembered STANDARD_DEVIATION 4.29 |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 1 Participants |
| Race (NIH/OMB) Black or African American | 1 Participants |
| Race (NIH/OMB) More than one race | 0 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 11 Participants |
| Region of Enrollment United States | 13 Participants |
| Sex: Female, Male Female | 6 Participants |
| Sex: Female, Male Male | 7 Participants |
| Tau | 3.38 pg/mL STANDARD_DEVIATION 0.97 |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | 0 / 13 |
| other Total, other adverse events | 0 / 13 |
| serious Total, serious adverse events | 0 / 13 |
Outcome results
Primary
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
| Arm | Measure | Value (COUNT_OF_PARTICIPANTS) |
|---|---|---|
| Gamma Stimulation Group | Drop Out | 1 Participants |
Primary
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
Population: Only data from participants who completed the full protocol were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Gamma Stimulation Group | Side Effects | 0.53 units on a scale | Standard Deviation 0.65 |
Secondary
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)
Population: Only data from participants who completed the full protocol were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Gamma Stimulation Group | Beta Amyloid Load Change | 0.0008 unitless ratio | Standard Deviation 0.006 |
p-value: 0.34Sign test
Secondary
Change in Tau
Plasma tau levels was assessed pre and post intervention. Change was calculated as post minus pre. Greater decrease is better.
Time frame: pre-tACS (baseline), post-tACS (after one month of treatment)
Population: Only data from participants who completed the full protocol were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Gamma Stimulation Group | Change in Tau | 0.27 pg/mL | Standard Deviation 0.72 |
p-value: 0.31Sign test
Secondary
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.
Time frame: pre-tACS (baseline), post-tACS (after one month of treatment)
Population: Only data from participants who completed the full protocol were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Gamma Stimulation Group | Memory: Fluency Change | 1.5 number of items named | Standard Deviation 2.6 |
p-value: 0.049Sign test
Secondary
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)
Population: Only data from participants who completed the full protocol were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Gamma Stimulation Group | Memory: Paired Associates Change | 11.5 percent correct | Standard Deviation 21 |
p-value: 0.083Sign test
Secondary
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)
Population: Only data from participants who completed the full protocol were analyzed.
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Gamma Stimulation Group | Memory: Recall Change | 1.5 words correct | Standard Deviation 2.1 |
p-value: 0.024Sign test