SMART Stimulation: Precision Neuromodulation of Cognition in Older Adults

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.

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.