tACS Improves Memory in Elders With Subjective Memory Complaints

Study Overview
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Brief Summary
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Subjective memory complaints (SMC), the main cognitive component of which is event memory, is a predictor of Alzheimer's disease in elderly people. The purpose of this study was to investigate the effect of transcranial alternating current stimulation (tACS) with theta frequency (6 Hz) on the medial prefrontal cortex in the improvement of episodic memory in individuals with SMC in a double blind, randomized, and sham-controlled parallel study. Sixteen participants with SMC received either active or sham theta tACS on the medial prefrontal cortex (mPFC). EEG was recorded and Rey Auditory Verbal Learning Test (RAVLT) was administered. The aim of the current study was to see if theta tACS over the mPFC can improve event memory in individuals with SMC and thus can be considered a potential therapeutic intervention for this population or not.

Official Title
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Remember NIBS? tACS Improves Memory Performance in Elders With Subjective Memory Complaints

Conditions
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Memory Deficits, tACS

Intervention / Treatment
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* Device: active tACS
* Device: sham tACS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Being 50 or older, Mini Mental State Examination (MMSE) grade from 27 to 30 Total score of 58 or more on the Everyday Memory Questionnaire (EMQ) no indications of depression and anxiety measured by Geriatric Depression Scale (GDS) and State-Trait Anxiety Inventory (STAI) No sign of dementia based on Diagnostic and statistical manual of mental disorder, 5th edition (DSM-V) criteria Exclusion Criteria: History of a major psychological or neurological condition History of head trauma leading to unconsciousness, Presence of metal in the head History of seizures Serious cardiovascular disease Use of medications with an impact on cognitive functions Recent use of alcohol or substance abuse

Ages Eligible for Study
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Minimum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Active tACS<br>Participants in this group received 20 minutes of active 6 Hz stimulation over the medial prefrontal cortex. | Device: active tACS<br>* transcranial alternating current stimulation is a non-invasive method of entraining specific frequency bands in the brain by applying weak intensities of electric current in a desired shape and phase to the desired brain regions.<br>|
| Sham Comparator: Sham tACS<br>Participants in this group received 20 minutes of sham stimulation over the medial prefrontal cortex. | Device: sham tACS<br>* transcranial alternating current stimulation is a non-invasive method of entraining specific frequency bands in the brain by applying weak intensities of electric current in a desired shape and phase to the desired brain regions.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in performance | Rey auditory-verbal learning test (RAVLT) | 25 minutes i.e., before versus after the stimulation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in EEG power in theta frequency band | Spectral analysis measuring power in different frequency bands | 30 minutes, i.e., before versus after stimulation | 
| Change in phase synchronization connectivity in theta frequency band | Phase relations between neural signals realized by means of phase-locking values (PLV) | 30 minutes, i.e., before versus after stimulation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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tACS, Episodic memory, medial Prefrontal Cortex, SMC