Modulation of Fear Extinction Processes Using Transcranial Electrical Stimulation

Not Applicable

Completed

• Conditions: Stress Related Disorder; Anxiety
• Interventions: Device: DC stimulation (1.5 milliampere, 20 minutes); Device: Sham stimulation (1.5 milliampere,30 seconds); Device: AC stimulation (1.5 milliampere,1.5 Hertz frequency)

• Registration Number: NCT02723188
• Lead Sponsor: Tel Aviv University

Brief Summary

The aim of this study is to examine the effects of transcranial electrical stimulation on processes associated with fear extinction in healthy humans.

Detailed Description

Research links the processes of fear conditioning and extinction to the treatment of anxiety and stress-related disorders. Moreover, considerable translational research examines the neural correlates of these processes. However, virtually no research in humans manipulates neural correlates of these processes, which limits basic-clinical integration. The present study aimed to use transcranial electrical stimulation (tES) to modulate processes associated with fear extinction in order to assess the potential utility of tES in enhancing exposure-based treatment. To this end, healthy participants underwent a three-day fear conditioning and extinction paradigm. Participants were randomly assigned into 3 groups, differing in terms of tES applied during the extinction learning phase (Day 2) and targeting the medial prefrontal cortex: 1) direct current (DC) stimulation, aimed at enhancing extinction learning; 2) alternate current (AC) stimulation, aimed at interfering with reconsolidation of the fear memory activated during the extinction phase; and 3) sham stimulation. The outcome measures (outlined next) involve the assessment of extinction recall during a test phase (Day 3). Successful modulation of extinction learning by tES would be reflected in enhanced extinction recall.

Study Timeline

• Study Start: 2014-09
• Primary Completion: 2015-04
• Study Completion: 2015-04
• Study First Submitted: 2016-03-24
• Study First Submitted QC: 2016-03-24
• Study First Posted: 2016-03-30
• Results First Submitted: 2016-10-26
• Status Verified: 2017-05
• Results First Submitted QC: 2017-05-13
• Last Update Submitted: 2017-05-13
• Results First Posted: 2017-06-14
• Last Update Posted: 2017-06-14

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 45

Inclusion Criteria

Not provided

Exclusion Criteria

• Self-reported major psychiatric condition
• Screening specific for electrical stimulation (psychotropic medication, metal implants in head, epilepsy or seizure history)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
DC: Direct current	DC stimulation (1.5 milliampere, 20 minutes)	Direct current electrical stimulation
Sham	Sham stimulation (1.5 milliampere,30 seconds)	Sham electrical stimulation
AC: Alternating current	AC stimulation (1.5 milliampere,1.5 Hertz frequency)	Alternating current electrical stimulation

Primary Outcome Measures

Name	Time	Method
Galvanic Skin Response (GSR)	During three-day experimental task	GSR was measured throughout the task using 2 standard electrodes on the fingers. Measurement units were in micro-Siemens; scores were square-root-transformed (a common method in GSR studies). A higher level of GSR in response to stimuli is taken to reflect greater physiological fear response, and thus worse in the context of the relevance of the study conditions to the treatment of anxiety disorders.; Scores were collected in response to presentation of the CS+ (the stimulus conditioned to be associated with an aversive outcome) and the CS- (the stimulus not conditioned to be associated with any outcome).

Secondary Outcome Measures

Name	Time	Method
Self-reported Fear Rankings	During three-day experimental task	Participants marked how fearful they are of stimuli used in the task on a single 10-point scale (1=not afraid, 10=extremely afraid). Higher scores therefore reflect greater fear and are worse in the context of treatment for anxiety disorders.; Scores were collected in response to presentation of the CS+ (the stimulus conditioned to be associated with an aversive outcome) and the CS- (the stimulus not conditioned to be associated with any outcome).