Noninvasive Brain Stimulation to Enhance Cognitive Training in Older Adults
Condition: Normal Aging
Study type: Interventional

Summary: 
      This research study explores the feasibility of pairing computer-based cognitive training
      (CBCT) with transcranial direct current stimulation (tDCS), a form of non-invasive brain
      stimulation, in order to enhance and preserve mental skills in older adults. The
      investigators aim to enhance participants ability to perform tasks of memory, attention,
      processing speed and other areas of cognition. Additionally, researchers are interested in
      the ability of the brain to adapt to change-neuroplasticity. Neuroplasticity is thought to
      impact how individuals respond to cognitive training and tDCS. In order to look at individual
      differences in neuroplasticity transcranial magnetic stimulation (TMS), a noninvasive brain
      stimulation technique, will be used. Individual responses to TMS can be used as a marker of
      neuroplastic changes in brain function, in order to reveal the relationship between brain
      plasticity and tDCS-induced changes in cognitive ability.
    

Detailed description: 
      Promising evidence suggests that cognitive training regimens may have some beneficial effects
      on cognition in older adults. However, the improvement from computer-based cognitive training
      (CBCT) diminish over time which highlights a fundamental challenge for CBCT interventions.
      Transcranial direct current stimulation (tDCS) can enhance certain cognitive skills,
      particularly when stimulation is combined with rehearsal of relevant behaviors. Importantly,
      these benefits have been shown to persist up to 2 months after the intervention.

      This study will lay the groundwork for larger scale studies that will combine CBCT with
      neuromodulation, potentially leading to the development of a persistent, transferrable,
      multimodal technique to preserve cognition in older adults. In this study, participants will
      be randomly assigned to receive either real or sham tDCS for 5 consecutive days in
      conjunction with CBCT. The participant's cognition will be assessed with a neuropsychological
      assessment at baseline, 1 week, 2 weeks, and 2 months in order to determine any changes.

      Additionally, transcranial magnetic stimulation (TMS) will be used to characterize the
      relationship between baseline differences in brain plasticity and cognitive changes induced
      by tDCS+CBCT. The effects of TMS on cortical activity have been shown to depend on a variety
      of neuroplasticity-related mechanisms. In this study, changes in motor physiology (called
      motor evoked potentials (MEPs)) induced by TMS will be used. Stimulation of the motor cortex
      with TMS induces robust, transient, and readily quantifiable changes in motor excitability,
      which are sensitive to changes in the mechanisms of neuroplasticity. Investigators
      hypothesize that individual variability in brain plasticity, measured by changes in MEP
      response to TMS, will predict the degree of cognitive benefit afforded by tDCS+CBCT.

      Study Visits:

      ---------------- Visit 1 - Consent and Screening (2 hours) Review enrollment documents and
      conduct baseline neuropsychological assessment

      ---------------- Visit 2 - Visit 5 - tDCS + CBCT (30 minutes) Subjects will receive either
      real or sham stimulation along with cognitive training

      --------------- Visit 6 - tDCS + CBCT & Follow-up (3 hours) Subjects will receive either real
      or sham stimulation along with cognitive training & follow-up neurospychological assessment

      --------------- Visit 7 - TMS (3 hours) Subjects will receive TMS in order to induce MEPs

      ------------ Visit 8 - 2 week follow-up (1 .5 hours) Follow-up neuropsychological assessment

      ----------- Visit 9 - 2 month follow-up (1.5 hours) Follow-up neuropsycological assessment
    

Intervention name(s): Transcranial Direct Current Stimulation; Computer-based cognitive therapy (CBCT)
Intervention type(s): Device; Behavioral
Intervention description(s): tDCS is a neuromodulatory technique that delivers a small electric current (about the equivalent of a 9V battery) to the head. A fixed current between 1 and 2 mA is typically applied. tDCS works by applying a positive (anodal) or negative (cathodal) current via electrodes to an area, facilitating the depolarization or hyperpolarization of neurons, respectively.; Repetitive, drill-like training usually presented in the form of a game that targets a specific cognitive construct.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants are assigned to either receive real or sham tDCS without the option of crossover.
Masking: Double (Participant, Investigator)
Primary purpose: Prevention
Keywords: non-invasive brain stimulation; cognition; transcranial direct current stimulation (tDCS)