tACS Improves Memory in Elders With Subjective Memory Complaints

University of Tehran16 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Enrollment

Conditions

Memory Deficits tACS

Interventions

Eligibility

Sex: ALLMin age: 50 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Change in performance

Rey auditory-verbal learning test (RAVLT)

Time frame: 25 minutes i.e., before versus after the stimulation

Secondary Outcomes

Change in EEG power in theta frequency band

Spectral analysis measuring power in different frequency bands

Time frame: 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)