Effect of Noninvasive Electrical Brain Stimulation on Memory at Different Times of Day in Younger and Older Adults

Effect of Noninvasive Electrical Brain Stimulation on Memory Performance at Different Times of Day in Younger and Older Adults

This study will investigate the extent to which tDCS to dorsolateral prefrontal cortex (or dlPFC) impacts memory performance as a function of time-of-day in younger and older adults.

Study Overview

• Status: Completed
• Conditions: Effect of tDCS on Memory in Older and Younger Adults
• Intervention / Treatment: Device: Active tDCS; Device: Sham tDCS

Detailed Description

Transcranial Direct Current Stimulation (tDCS) is the safest and most accessible, non-invasive brain stimulation technique available for testing causal links between different brain regions and functions, by manipulating cognitive abilities. By identifying key experimental factors that can improve the reliability and robustness of stimulation effects on cognitive performance in different age groups, this project should lead to the widespread adoption of these design features in future applications. This study will investigate the extent to which tDCS to dorsolateral prefrontal cortex (or dlPFC) impacts recollection accuracy and working memory performance as a function of time-of-day in younger and older adults. Moreover, this study will test the extent that tDCS to dlPFC impacts memory performance by impacting information-specific processes and/or cognitive control processes that operate across different types of information, thereby informing basic theories of how dlPFC contributes to memory in younger and older adults.

• Study Type: Interventional
• Enrollment (Actual): 271
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Chicago, Illinois, United States, 60637
      • University of Chicago

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Right-handed (according to the Edinburgh Handedness Inventory)
• Normal or corrected vision
• Fluent in English (started learning by age 6)
• Ability to understand and provide informed consent for study procedures, and to comply - with study procedures for the entire length of the study.
• For individuals in the 'younger adults' group, must be between 18 and 30 years of age
• For individuals in the 'older adults' group, must be between 60 and 75 years of age
• A score of 23 or above on the Montreal Cognitive Assessment (out of 30, education-corrected) is required. This is to minimize the inclusion of suspected mild cognitive impairment (MCI) or dementia, targeting individuals that score in the normal range according to the recent meta-analysis of MoCA's ability to differentiate normal aging from MCI in Carson et al. (2018, Int. J of Geriatric Psychiatry).
• Performance above threshold on the episodic memory task during the baseline session. The threshold is defined as having a hit rate that is at least 5% greater than the false alarm rate, where hit rate is defined as the number of studied items identified as studied, divided by the total number of studied items, and false alarm rate is defined as the number of new items identified as studied, divided by the total number of new items. We don't anticipate this threshold to exclude many, if any subjects.

Exclusion Criteria:

• Neuropsychological conditions associated with cognitive decline or seizure
• Cochlear implants or metal in the brain/skull (except titanium)
• Psychoactive medications, or diagnosis of depression, bipolar disorder, or any psychotic diagnoses
• History of excessive use (clinically treated) alcohol or narcotics
• Hospitalization for head trauma (e.g. concussions) in the past 5 years
• Individuals above a threshold score on an assessment of depression, specifically, a score of 10 or above on the Patient Health Questionnaire (PHQ-9)(Manea et al., 2012)
• Risk of pregnancy
• Low tolerance of skin irritation
• Prior brain stimulation experience (self-report)
• Ongoing cognitive or sensory deficits/symptoms from a previous (or current) COVID-19 infection.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Older, active tDCS, dlPFC; Older adults (ages 60-75) randomized to this arm will receive 2 sessions of active tDCS stimulation (Soterix Medical) delivered to the left dorsolateral prefrontal cortex. One session will occur in the morning (8 or 9am) and one will occur on a separate day in the afternoon (3 or 4pm). 2.	Device: Active tDCS; The brain is stimulated for 20 minutes with mild electrical current (maximum 2 mA) with two 7 cm x 5 cm electrodes placed on the scalp, using a standard 1x1 tDCS Clinical Trials device (Soterix Medica, NY), specialized for double-blinding.
Sham Comparator: Older, sham tDCS, dlPFC; Older adults (ages 60-75) randomized to this arm will receive 2 sessions of sham tDCS stimulation (Soterix Medical) delivered to the left dorsolateral prefrontal cortex. One session will occur in the morning (8 or 9am) and one will occur on a separate day in the afternoon (3 or 4pm).	Device: Sham tDCS; The brain is not stimulated for 20 minutes with mild electrical current, but instead a sham procedure is administered using a standard 1x1 tDCS Clinical Trials device (Soterix Medica, NY), specialized for double-blinding.
Experimental: Younger, active tDCS, dlPFC; Younger adults (ages 18-30) randomized to this arm will receive 2 sessions of active tDCS stimulation (Soterix Medical) delivered to the left dorsolateral prefrontal cortex. One session will occur in the morning (8 or 9am) and one will occur on a separate day in the afternoon (3 or 4pm).	Device: Active tDCS; The brain is stimulated for 20 minutes with mild electrical current (maximum 2 mA) with two 7 cm x 5 cm electrodes placed on the scalp, using a standard 1x1 tDCS Clinical Trials device (Soterix Medica, NY), specialized for double-blinding.
Sham Comparator: Younger, sham tDCS, dlPFC/parietal; Younger adults (ages 18-30) randomized to this arm will receive 2 sessions of sham tDCS stimulation (Soterix Medical) delivered to either the left dorsolateral prefrontal cortex (area F3 using the 10-20 EEG system, n = 25), or the left parietal cortex (area P5 using the 10-20 EEG system, n = 25). One session will occur in the morning (8 or 9am) and one will occur on a separate day in the afternoon (3 or 4pm).	Device: Sham tDCS; The brain is not stimulated for 20 minutes with mild electrical current, but instead a sham procedure is administered using a standard 1x1 tDCS Clinical Trials device (Soterix Medica, NY), specialized for double-blinding.
Active Comparator: Younger, active tDCS, parietal cortex; Younger adults (ages 18-30) randomized to this arm will receive 2 sessions of active tDCS stimulation (Soterix Medical) delivered to the left parietal cortex (area P5 using the 10-20 EEG system). One session will occur in the morning (8 or 9am) and one will occur on a separate day in the afternoon (3 or 4pm).	Device: Active tDCS; The brain is stimulated for 20 minutes with mild electrical current (maximum 2 mA) with two 7 cm x 5 cm electrodes placed on the scalp, using a standard 1x1 tDCS Clinical Trials device (Soterix Medica, NY), specialized for double-blinding.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Episodic Memory Performance	To measure episodic memory performance, participants will perform a recollection task. They will first study picture and word stimuli (encoding phase). On the subsequent memory test (retrieval phase), participants will be asked to differentiate between studied and non-studied items, as well as recollecting the previous format for studied items (i.e. recollecting the picture or word). For each tested item, participants will also be asked to make a confidence judgement about their response. The primary dependent variable (DV) will be the proportion of studied items attributed to the correct source minus the proportion of nonstudied items incorrectly attributed to that same source.	This task is performed immediately after tDCS is administered, and lasts approximately 20 minutes.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Working Memory Performance	To measure working memory performance, participants will perform two versions of the N-back task -- a verbal version (i.e., presenting the numbers 1-9 in a varied sequence) and a visuospatial version (i.e., presenting a colored square in one of 9 locations on a 3x3 grid in a varied sequence). The primary DV will be working memory accuracy: proportion of targets correctly identified minus the proportion of lures incorrectly endorsed.	This task lasts approximately 10 minutes and is performed immediately after the episodic memory task (approximately 20 minutes after the end of the tDCS session).

Collaborators and Investigators

• Sponsor: University of Chicago
• Collaborators: National Institute on Aging (NIA)
• Investigators: Principal Investigator: David Galllo, University of Chicago

Study record dates

Study Major Dates

• Study Start (Actual): March 8, 2019
• Primary Completion (Actual): December 15, 2022
• Study Completion (Actual): December 15, 2022

Study Registration Dates

• First Submitted: October 26, 2018
• First Submitted That Met QC Criteria: October 26, 2018
• First Posted (Actual): October 30, 2018

Study Record Updates

• Last Update Posted (Actual): May 14, 2024
• Last Update Submitted That Met QC Criteria: April 17, 2024
• Last Verified: April 1, 2024

More Information

Terms related to this study

• Keywords: Transcranial Direct Current Stimulation; Memory; Prefrontal Cortex
• Other Study ID Numbers: IRB18-1246; R21AG060444 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: The investigators will post data on the Open Science Framework (online), so that de-identified data will be made available to any outside researcher. Shared data will include, at a minimum, an excel data file used to summarize all participant cognitive data. Any computer scripts or stimuli used for task development also will be shared.
• IPD Sharing Time Frame: Study data will become available within 6 months of publication of the relevant results.
• IPD Sharing Access Criteria: The investigators will use the Open Science Framework for making data available.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF; ANALYTIC_CODE; CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes
• product manufactured in and exported from the U.S.: Yes