Functional Connectivity as a Biomarker of rTMS
Condition: Traumatic Brain Injury
MeSH terms: Brain Injuries; Brain Injuries, Traumatic
Study type: Interventional
Phase: Phase 1/Phase 2

Summary: 
      Background:

      Traumatic brain injury (TBI) damages the connections between brain cells. This can lead to
      problems like memory loss. Repetitive transcranial magnetic stimulation (rTMS) can help
      improve connections between brain areas in healthy people. Researchers want to see if it can
      be useful in patients with memory problems after TBI.

      Objective:

      To see how repetitive transcranial magnetic stimulation can be used to improve the
      connections between parts of the brain and whether this will lead to changes in memory.

      Eligibility:

      Adults 18-50 years old with TBI who can speak and write in English.

      Healthy volunteers the same age and English ability.

      Design:

      Participants will be screened with a neurological exam and may have a urine pregnancy test.

      Participants with TBI will have 7-15 visits. Healthy volunteers will have 2-8 visits.

      At the visits, participants will have all or some of the following:

        -  MRI for about 1 hour. Participants will lie in a machine that takes pictures in a
           magnetic field. Participants will do some memory tasks.

        -  Memory and attention tasks with pictures and with a computer

        -  Questions about their mental state and well-being

        -  TMS: A wire coil is held on the scalp and a short electrical current passes through it.
           Participants will hear a click and feel a pulling or twitch. They may be asked to make
           simple movements. rTMS is repeated magnetic pulses in short bursts. They will have this
           for about 20 minutes.

      A week after the last visit, some participants will return for a memory test.
    

Detailed description: 
      Objective: To use resting state functional connectivity (FC) as a biomarker of synaptic
      modulation by repetitive transcranial magnetic stimulation (rTMS) in paradigms intended to
      improve memory and learning. Ancillary outcomes include the effects of rTMS on the
      interaction between the explicit implicit memory systems.

      Study population: Healthy adult volunteers

      Design: The study contains two experiments. Experiment 1 is designed to establish the number
      of rTMS sessions required to produce a meaningful change in resting parieto-hippocampal FC in
      healthy subjects. Experiment 2 will replicate a prior experiment which used rTMS to enhance
      the explicit memory system in healthy subjects, and look for potential effects on the
      implicit system. This intervention will be contrasted with a negative control condition
      (vertex stimulation) in a between-groups design.

      Outcome measures: The primary outcome measure is the change in FC produced by serially
      applied rTMS and improvement in explicit memory. We will explore whether enhancement of the
      explicit system has effects on resting state connectivity in the implicit system and whether
      white matter integrity predicts changes in FC in healthy subjects.
    

Intervention name(s): rTMS
Intervention type(s): Device
Intervention description(s): Altering the connectivity of trans-synaptic pathways
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Explicit Memory; Implicit Memory; Memory Disorder