Anxiety & Depression Association of America

A Neurosensory Account of Anxiety and Stress

Purpose

This study will take a basic neuroscience approach to investigate pathological mechanisms underlying PTSD. Additionally, the study aims to identify how Transcranial Alternating Current Stimulation (tACS) brain stimulation can modulate and correct neural networks and related emotions of anxious arousal and hypervigilance, with the goal of assessing tACS brain stimulation technology as a novel intervention for symptoms of anxiety.

Conditions

Threat-related Sensory Cortical (SC) Disinhibition
Posttraumatic Stress Disorder (PTSD)

Eligibility

Eligible Ages: Between 18 Years and 50 Years
Eligible Sex: All
Accepts Healthy Volunteers: Yes

Inclusion Criteria

Right-handed - With normal or corrected-to-normal vision and normal olfaction - Between the ages of 18 and 50 years - Meeting the tACS screening criteria (see List I below; e.g., lack of a serious head injury or loss of consciousness) - Patients: Diagnosis of PTSD - Patients: If taking psychotropic medications, medication stability in the past 2 months - If having mild substance use disorder (for patients) or occasional substance use, abstention from use 48 hours before the experiment.

Exclusion Criteria

A history of diagnosis for a major medical illness (e.g., cancer, metabolic syndrome, cardiovascular disease, inflammatory disorders) or a neurological disorder (e.g., seizure, stroke, Parkinson's disease). - Patients: Concurrent Axis I diagnosis (depression, anxiety, and mild substance use disorder are allowed given their high comorbidity with PTSD). - Healthy controls: A history of diagnosis for a Diagnostic and Statistical Manual of Mental Disorders (DSM)-5 Axis I disorder or current use of psychoactive medications. - Severe psychiatric instability or severe situational life crises, including evidence of being actively suicidal or homicidal, or any behavior that poses an immediate danger to self or others. - History of head trauma with unconsciousness (> 5 minutes) - Report that they regularly drink 3 or more alcoholic beverages a day. - Report that they are unable to abstain from substance use (including alcohol, nicotine, cannabis, amphetamines, narcotics, solvents, cocaine, hallucinogens, tranquilizers, barbiturates, etc.) or sleep medication for 48 hours before being scanned. - Are on calcium channel blockers (e.g., verapamil, nifedipine) or alpha-blockers (e.g., prazosin, terazosin) and are unable to stop these medications for a 48-hour period prior to scanning (to exclude the impact of these medications on the interpretation of fMRI/EEG). - Failed Urine Drug Screening Test: A rapid urine screening test that utilizes monoclonal antibodies to detect elevated levels of specific drugs (including alcohol, amphetamines, benzodiazepines, barbiturates, cocaine, marijuana, opiates, etc.) in urine (iCup) - Pregnancy based on urine test. The safety of magnetic resonance (MR) systems has not been established for fetuses - Having electrically, magnetically, or mechanically activated implants (e.g., cardiac pacemakers), because the electromagnetic fields produced by the MR system may interfere with the operation of these devices.

Study Design

Phase: N/A
Study Type: Interventional
Allocation: Randomized
Intervention Model: Parallel Assignment
Primary Purpose: Treatment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)

Arm Groups

Arm	Description	Assigned Intervention
Experimental Transcranial Alternating Current Stimulation (tACS)		Device: Transcranial Alternating Current Stimulation (tACS) A weak electrical current will be passed through the scalp over targeted cortical regions via a transcranial electrical stimulation system (Soterix Medical, Inc), for a span of 10 to 40 minutes at a time. Participants will receive a 2 milliamp (mA) sinusoidal current oscillating at individual participants' baseline peak alpha frequencies (PAF; 7-13 Hz), which will be determined by a 3-min resting state EEG recording during the setup. Current intensities will be modified to address individual participants' subjective reports of discomfort, with a maximum intensity of 2 mA. Stimulation electrodes will be placed within an EEG cap fitted over the participant's head. Device: Sham for Transcranial Alternating Current Stimulation (tACS) Stimulation electrodes will be placed on the scalp, but no current will be passed. Stimulation electrodes will be placed within an EEG cap fitted over the participant's head.
Sham Comparator Sham for Transcranial Alternating Current Stimulation (tACS)		Device: Sham for Transcranial Alternating Current Stimulation (tACS) Stimulation electrodes will be placed on the scalp, but no current will be passed. Stimulation electrodes will be placed within an EEG cap fitted over the participant's head.
Active Comparator Active Control - Transcranial Random Noise stimulation (tRNS)		Device: Transcranial Random Noise stimulation (tRNS) A weak electrical currents will be passed through the scalp over targeted cortical regions via a transcranial electrical stimulation system (Soterix Medical, Inc), for a span of 10 to 40 minutes at a time. Participants will receive a 2 mA sinusoidal current oscillating at random frequency (1-200 Hz). Current intensities will be modified to address individual participants' subjective reports of discomfort, with a maximum intensity of 2 mA. Stimulation electrodes will be placed within an EEG cap fitted over the participant's head.

Recruiting Locations

More Details

Status: Recruiting
Sponsor: The University of Texas Health Science Center, Houston

Study Contact

Wen Li, PhD
(713) 486-2700
Wen.Li.1@uth.tmc.edu

Detailed Description

This study includes experiments 2 & 3 to address Aim 3--threat-related SC disinhibition and Sensory-Prefrontal-cortex-Amygdala (SPA) pathology in PTSD. The goal of this study is to develop and test a novel pathophysiology of PTSD by integrating sensory cortical (SC) and amygdala-prefrontal cortex (PFC) dysfunctions into a tripartite Sensory-Prefrontal-Cortex-Amygdala (SPA) model. The investigators will recruit 80 healthy subjects and 80 patients with PTSD in a randomized, double-blind, controlled design, where they be randomly assigned to 1) Transcranial Alternating Current Stimulation (tACS) at individual alpha peak frequency (active condition); 2) sham control tACS; or 3) active control, which will be transcranial random noise stimulation (tRNS) (random frequency 1-200 Hz). Simultaneous EEG/fMRI recordings and behavioral responses will be acquired before and after tACS/sham tACS/tRNS stimulation. During tACS/sham tACS/tRNS stimulation, stimulation electrodes will be placed inside the holders of an EEG cap attached to the head of the participant. Experiments 2 & 3 include a visual search task and an olfactory detection task, respectively, and both experiments include threat and neutral stimuli.

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.