Assessing the Clinical Utility of tACS
October 4, 2017 updated by: Wen Li, Florida State University
Assessing the Clinical Utility of tACS in the Treatment of Anxious Arousal and Sensory Sensitivity
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.
Study Overview
Status
Completed
Conditions
Intervention / Treatment
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.
Study Type
Interventional
Enrollment (Actual)
38
Phase
- Not Applicable
Participation Criteria
Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.
Eligibility Criteria
Ages Eligible for Study
18 years to 60 years (ADULT)
Accepts Healthy Volunteers
Yes
Genders Eligible for Study
All
Description
Inclusion Criteria:
- Right-handed
Exclusion Criteria:
- History of severe neurological disorder or traumatic brain injury
- Psychotropic medication use
- Metal plates/implants in head
- Pregnancy
- Implanted medical devices (e.x. pacemaker)
Study Plan
This section provides details of the study plan, including how the study is designed and what the study is measuring.
How is the study designed?
Design Details
- Primary Purpose: TREATMENT
- Allocation: RANDOMIZED
- Interventional Model: PARALLEL
- Masking: SINGLE
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
|
EXPERIMENTAL: Active
Participants within the Active condition receive 30 minutes of alpha-frequency Transcranial Alternating Current Stimulation (tACS) stimulation for four consecutive days.
Participants are stimulated at their baseline peak alpha frequency, or the frequency at which they exhibit maximal power within the 8 to 12 Hz range.
Stimulation was administered over occipitoparietal sites, where tACS current models showed maximal effect over the dorsal extrastriate.
|
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.
|
|
SHAM_COMPARATOR: Sham Control
Participants within the Sham condition receive 30 minutes of sham Transcranial Alternating Current Stimulation for four consecutive days, during which no current was passed.
To control for awareness of the Sham stimulation, all Sham control participants receive a brief, 10 second pulse of random noise stimulation at the beginning and end of the 30 minutes.
|
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.
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Immediate and lasting changes in alpha oscillatory power and directed, long-range cortico-cortical connectivity.
Time Frame: Immediately before, immediately after, and 30 minutes after stimulation on the first day. Immediately before (24 hours after most recent stimulation), immediately after, and 30 minutes after stimulation on the final (fourth) day.
|
Occipitoparietal alpha power and long-range, directed oscillatory connectivity within the alpha frequency will be assessed from 2 minutes of eyes-open, resting-state electroencephalogram (EEG) activity.
Oscillatory power will be estimated using the multitaper spectral estimation technique, averaging over the alpha frequency bin of 8-12 Hz.
Directed connectivity will be assessed using spectral Granger causality within the 8-12 Hz range.
Specifically, long-range, posterior-frontal connectivity with be assessed.
|
Immediately before, immediately after, and 30 minutes after stimulation on the first day. Immediately before (24 hours after most recent stimulation), immediately after, and 30 minutes after stimulation on the final (fourth) day.
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Immediate and lasting reductions in anxious arousal
Time Frame: Immediately before, immediately after, 30 minutes after stimulation on the first and final day. Immediately before (24 hours after most recent stimulation) and immediately after stimulation on the second and third days.
|
Self-report ratings of subjective units of anxious arousal are acquired using a visual analog scale, ranging from 0 (not at all anxiously aroused) to 100 (extremely anxiously aroused).
|
Immediately before, immediately after, 30 minutes after stimulation on the first and final day. Immediately before (24 hours after most recent stimulation) and immediately after stimulation on the second and third days.
|
|
Immediate and lasting changes in affective perception of sensory stimuli
Time Frame: Immediately before, immediately after, and 30 minutes after stimulation on the first day. Immediately before (24 hours after most recent stimulation), immediately after, and 30 minutes after stimulation on the final (fourth) day.
|
Pleasantness ratings of neutral and negative olfactory and auditory stimuli are acquired on a visual analog scale, ranging from 0 (extremely unpleasant) to 100 (extremely pleasant).
Auditory stimuli consist of a simple tone (neutral) and scream (negative) at three different intensities (quiet, medium, and loud), each presented once for 2 seconds through headphones.
Olfactory stimuli consist of a neutral odor (acetophenone) and negative odor (burning rubber), diluted in mineral oil for three different intensities (weak, medium, strong).
Approximately 3 mL of each odor are presented in 30 mL amber bottles, upon which participants are asked to take one steady sniff.
|
Immediately before, immediately after, and 30 minutes after stimulation on the first day. Immediately before (24 hours after most recent stimulation), immediately after, and 30 minutes after stimulation on the final (fourth) day.
|
Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Sponsor
Study record dates
These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.
Study Major Dates
Study Start (ACTUAL)
July 29, 2016
Primary Completion (ACTUAL)
March 31, 2017
Study Completion (ACTUAL)
March 31, 2017
Study Registration Dates
First Submitted
October 4, 2017
First Submitted That Met QC Criteria
October 4, 2017
First Posted (ACTUAL)
October 9, 2017
Study Record Updates
Last Update Posted (ACTUAL)
October 9, 2017
Last Update Submitted That Met QC Criteria
October 4, 2017
Last Verified
October 1, 2017
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
- 2017.20700
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
UNDECIDED
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
No
Studies a U.S. FDA-regulated device product
No
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.