Multiparameter Optimized tES for Memory in Aging

With an aging population worldwide, it is critical to develop effective interventions promoting healthy cognitive aging. Transcranial electrical stimulation (tES) is a promising but not fully realized noninvasive brain stimulation approach that could improve memory. This study investigates the behavioral and electrocortical effects of personalized tES in aging to determine whether whether optimal dosing, electrode placements, and waveforms elicit stronger responses.

With an aging population worldwide, it is critical to develop effective interventions promoting healthy cognitive aging. A key component of healthy cognition is intact working memory, an executive neural process holding information temporarily. With increasing age, working memory capacity decreases and is associated with a loss of independence, thus incentivizing the need to retain a healthy working memory capacity. In addition to facilitating healthy aging, developing a method that improves working memory could help those diagnosed with mild cognitive impairment (MCI) and Alzheimer's Disease (AD), which is currently is the 6th leading cause of death in the US and has an annual economic burden of $305 billion.

A potential approach to improve working memory is transcranial electrical stimulation (tES), a noninvasive brain stimulation method using scalp electrodes to deliver low electrical currents of 2 milliamps (mA) over the cortical target. While some prior studies have shown that prefrontal tES can improve working memory in older adults, there are small meta-analytic effect sizes and no FDA-approved indications to date. These mixed results could be due to applying one-size-fits-all and suboptimal tES parameters. In this study, the investigators will test the effects of personalized parameters, including dosing, electrode positioning, and waveforms compared to standard tES and placebo.

Eligibility Criteria:
Inclusion Criteria:

* 50 - 85 y.o.
* Endorse good health with no history of mental or physical illness
* Willingness to adhere to the study schedule and assessments
* Able to read consent document and provide informed consent.
* English is a first or primary fluent language.

Exclusion Criteria:

* Any current psychiatric diagnosis or current Clinical Global Impression ratings of psychiatric illness \> 1
* Neurodevelopmental disorders, history of Central Nervous System (CNS) disease, concussion, overnight hospitalization, or other neurologic sequela, tumors, seizures, meningitis, encephalitis, or abnormal CT or MRI of the brain
* Any psychotropic medication is taken within 5 half-lives of procedure time
* Any head trauma resulting in loss of consciousness
* Visual impairment (except the use of glasses)
* Inability to complete cognitive testing
* Active participation or plan for enrollment in another evidence-based clinical trial affecting the psychosocial function
* Repeated abuse or dependence upon drugs (excluding nicotine and caffeine) or taking medications including stimulants, modafinil, thyroid medication, or steroids
* Implanted devices/ferrous metal of any kind
* History of seizure or epilepsy, currently taking medications that lower seizure thresholds
* Claustrophobia or other conditions that would prevent the MRI assessment.
* Pregnancy (or suspected/possible pregnancy or plan to become pregnant in the short term).
* Urine Pregnancy Test: If the subject is a woman of childbearing potential and /or a man capable of fathering a child before, during, and/or after participation precautions should be taken. Examples of acceptable methods of birth control for participants involved in the study include birth control pills, patches, Intrauterine Devices (IUD), condoms, sponges, diaphragm with spermicide, or avoiding sexual activity that could cause the subject to become pregnant.
* Inability to adhere to the treatment schedule.
* Inability to fit the wearable device to the user's head.