SMART Stimulation: Precision Neuromodulation of Cognition in Older Adults

The current study will investigate methods for enhancing cognitive training (CT) effects in healthy older adults by employing a combination of interventions facilitating neural plasticity and optimizing readiness for learning. A pilot randomized clinical trial will examine the individual and combined impact of pairing cognitive training with transcranial direct current stimulation (tDCS). A precision dosing algorithm will be used to determine the appropriate levels of current and location of electrodes to deliver current using tDCS.

Study Overview

• Status: Completed
• Conditions: Aging
• Intervention / Treatment: Device: tDCS; Behavioral: cognitive training

• Study Type: Interventional
• Enrollment (Actual): 33
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Gainesville, Florida, United States, 32610
      • McKnight Brain Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years to 89 years (Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Men and women
• Age: 65 to 89 years
• English speaking
• Physically mobile
• Working memory function between 0-75th percentile determined by screening results on the POSIT Baseline Cognitive Training computerized tasks.

Exclusion Criteria:

• Neurological disorders (e.g., dementia, stroke, seizures, traumatic brain injury).
• Evidence of dementia (NACC UDS scores of 1.5 standard deviations below the mean for age, sex and education adjusted norms in a single cognitive domain on the task).
• Past opportunistic brain infection
• Major psychiatric illness (schizophrenia, intractable affective disorder, current substance dependence diagnosis or severe major depression and/or suicidality.
• Unstable (e.g., cancer other than basal cell skin) and chronic (e.g, severe diabetes) medical conditions.
• MRI contraindications (e.g., pregnancy, claustrophobia, metal implants that are contraindicated for MRI).
• Physical impairment precluding motor response or lying still for 1 hr and inability to walk two blocks without stopping.
• Certain prescription medications may possibly reduce effects otherwise induced by the tDCS stimulation protocol.
• Hearing or vision deficits that will not allow for standardized cognitive training stimulation; ie colorblindness, inability to hear through headphones (with or without hearing aids), macular degeneration or other significant diseases that cause severe loss of vision. If vision is corrected with lenses to appropriate levels, then participant will be eligible.
• Left handedness, as those with left-handedness have a higher percentage rate of atypical functional lateralization for brain functions, which would significantly interfere with interpretability of brain data.
• Participants with precision tDCS dosage of >4.0mA required will be excluded due to limitations of tDCS device (maximum output of 4.0 mA). The maximum output of 4.0 mA reflects a technical limitation of the device design rather than a safety threshold.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Factorial Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Optimized tDCS + Cognitive Training; A Soterix Clinical Trials Direct Current Stimulator will apply 20 minutes of up to 4.0mA direct current through two biocarbon rubber electrodes covered with at least 5mm-thick conductive electrode paste buffer, and placed over the optimized locations based on the international 10-20 system by using a combination of 10-20 EEG cap measurement and a stereotactic neuronavigation system. Stereotactic neuronavigation will be used as needed and may not be used on all participants.	Device: tDCS; During tDCS, a weak electrical current is applied to the scalp that penetrates skin, bone, CSF and the meninges to stimulate underlying cortical and subcortical tissue; Behavioral: cognitive training; Cognitive Training (CT) will involve up to 10 hours of training over 2-weeks (10 days). CT employs a PositScience BrainHQ suite via its researcher portal. These tasks are web-based and multi-platform (i.e., Windows, Mac). Participants will be randomly assigned to training on 4 tasks focusing on working memory or 4 tasks focusing on attention/speed of processing.
Sham Comparator: Sham tDCS + Cognitive Training; Sham stimulation is performed with the same device and all procedures will be identical except for the duration of stimulation. Participants will receive 30 seconds of up to 4 mA of direct current stimulation at the beginning of the session. Participants habituate to the sensation of tDCS within 30-60 seconds of stimulation. This procedure provides the same sensation of tDCS without the full duration of stimulation, making it a highly effective sham procedure.	Device: tDCS; During tDCS, a weak electrical current is applied to the scalp that penetrates skin, bone, CSF and the meninges to stimulate underlying cortical and subcortical tissue; Behavioral: cognitive training; Cognitive Training (CT) will involve up to 10 hours of training over 2-weeks (10 days). CT employs a PositScience BrainHQ suite via its researcher portal. These tasks are web-based and multi-platform (i.e., Windows, Mac). Participants will be randomly assigned to training on 4 tasks focusing on working memory or 4 tasks focusing on attention/speed of processing.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
N-Back Working Memory	Change in working memory performance on the N back working memory MRI task from baseline to post test will be assessed. Post test will occur approximately two weeks following baseline. The N-back working memory task will be completed during the MRI scan at both baseline and post test assessments. Working memory performance will be defined as a composite of reaction time and accuracy for two back trials. Specifically Target Accuracy percent correct and average correct target reaction time in milliseconds. Percent changes were calculated for Target Accuracy and Reaction Time in the form of (post test-pre test)/pre test. Since the direction of improvement is opposite for the two variables (i.e. higher Accuracy is better and lower Reaction Time is better), the reaction time percent change was multiplied by -1 to ensure a larger number indicated improved performance. To create a composite these two percent changes (Target Accuracy and Reaction Time) were averaged into a single value.	Baseline to post test. Post test will occur approximately two weeks following baseline.

Collaborators and Investigators

• Sponsor: University of Florida
• Collaborators: Soterix Medical

Study record dates

Study Major Dates

• Study Start (Actual): January 17, 2023
• Primary Completion (Actual): June 3, 2024
• Study Completion (Actual): June 3, 2024

Study Registration Dates

• First Submitted: April 7, 2022
• First Submitted That Met QC Criteria: May 11, 2022
• First Posted (Actual): May 17, 2022

Study Record Updates

• Last Update Posted (Actual): June 26, 2025
• Last Update Submitted That Met QC Criteria: June 25, 2025
• Last Verified: October 1, 2024

More Information

Terms related to this study

• Keywords: cognitive training; tdcs
• Other Study ID Numbers: IRB202100953

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.: No