SMART Stimulation: Precision Neuromodulation of Cognition in Older Adults

Study Overview
=================
Brief Summary
-----------------
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.

Official Title
-----------------
SMART Stimulation: Precision Neuromodulation of Cognition in Older Adults

Conditions
-----------------
Aging

Intervention / Treatment
-----------------
* Device: tDCS
* Behavioral: cognitive training


Participation Criteria
=================
Eligibility Criteria
-----------------
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.

Ages Eligible for Study
-----------------
Minimum Age: 65 Years
Maximum Age: 89 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Factorial Assignment
Interventional Model Description: Arm 1 will receive optimized tDCS paired with cognitive training. Arm 2 will receive sham tDCS paired with cognitive training.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Optimized tDCS + Cognitive Training<br>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<br>* 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<br>Behavioral: cognitive training<br>* 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.<br>|
| Sham Comparator: Sham tDCS + Cognitive Training<br>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<br>* 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<br>Behavioral: cognitive training<br>* 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.<br>|

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. | Baseline to post test. Post test will occur approximately two weeks following baseline. | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
tdcs, cognitive training