Assessing the Clinical Utility of tACS
Condition: Anxiety Disorders and Symptoms; Sensory Disorders; Hypervigilance; Post Traumatic Stress Disorder
MeSH terms: Sensation Disorders; Stress Disorders, Traumatic; Anxiety Disorders; Stress Disorders, Post-Traumatic
Study type: Interventional

Summary: 
      The present study seeks to evaluate the clinical utility of repeated transcranial alternating
      current stimulation (tACS) by assessing long-term, lasting changes in oscillatory activity
      and subsequent changes in related behavioral processes of anxious arousal and sensory
      sensitivity. To date, only transient effects of tACS have been reported, lasting no longer
      than 30 to 70 minutes. In order to be truly impactful within a clinical setting, however,
      evidence for long-term effects of tACS is needed.
    

Detailed description: 
      Recent years have witnessed increasing recognition of "oscillopathies", neuropsychiatric
      disorders characterized by aberrations in the neural oscillations that orchestrate various
      mental activities. Transcranial alternating current stimulation (tACS) provides an effective
      way to directly modulate these oscillations in a non-invasive and frequency-specific manner,
      offering groundbreaking insights into the workings of the brain and, importantly, the
      development of novel treatments for these oscillopathies. However, evidence is lacking for
      the ability of tACS to induce long-term neural plasticity and lasting behavioral changes,
      which is critical for establishing the clinical utility of this novel intervention.

      Here, we are administering 30 minutes of alpha-frequency tACS over occipitoparietal sites for
      four consecutive days to evaluate both transient and long-term changes in alpha oscillatory
      power and long-range, directed oscillatory connectivity. As both anxious arousal and sensory
      sensitivity are highly related to alpha oscillations, as well as numerous neuropsychiatric
      disorders, changes in these behavioral outcomes were subsequently evaluated to assess
      clinically-relevant outcomes of the repeated tACS protocol.
    

Intervention name(s): Transcranial Alternating Current Stimulation
Intervention type(s): Device
Intervention description(s): Transcranial Alternating Current Stimulation passes a weak, 2 mA sinusoidal current through the scalp to the cortex at a specified frequency. Previous evidence suggests this exogenous sinusoidal stimulation interacts with the endogenous, cortical sinusoidal oscillatory activity, resulting in modulations of cortical oscillations. The intervention is non-invasive and virtually painless with no lasting adverse side-effects.
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants were randomly assigned to either an Active or Sham Control group. The Active group received the 30 minutes of alpha-tACS for four consecutive days, whereas the Sham Control group received Sham (no) stimulation.
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Oscillations; Non-invasive Brain Stimulation; Transcranial Alternating Current Stimulation