Neurophysiological Correlates of Exposition Therapy in Spider Phobia

Study Overview
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Brief Summary
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This study aims to investigate the neurophysiological correlates of spider phobia and its treatment with CBT based Exposure Therapy. This is the first study to investigate the neurophysiological correlates of Exposure Therapy in situ by means of functional Near-Infrared Spectroscopy (fNIRS). 30 spider phobic patients will be assessed and randomly allocated to 5 sessions of exposure therapy or waiting-list. Further, 30 non-phobic control subjects will be assessed (primary assessment only). During Exposure Therapy, changes in blood oxygenation will be measured with fNIRS in areas of the Cognitive Control Network. Regions of interest are the bilateral dorsolateral prefrontal cortex (DLPFC), bilateral inferior frontal gyrus (IFG) and somatosensory association cortex (SAC). Before the treatment, subjects will have one session of psychoeducation in which the rationale for the treatment is explained. In each therapy session subjects are exposed to 20 trials (each lasting 40s) of guided exposure by a psychotherapist. Further, 20 control trials of equal length are assessed in which subjects work with an earthworm. During the therapy additional anxiety coping strategies (e.g., controlled breathing, attention refocusing, cognitive reappraisal) are trained. After the treatment or waiting-list phase, treatment conditions are switched: The waiting list will be treated and the treated subject will wait for approximately 6 weeks. Before treatment (primary assessment), after treatment (secondary assessment) and after study completion (final assessment), additional combined NIRS EEG measurements are done. On a peripheral physiological level heart rate and EMG of the facial corrugator supercilii are measured. During these measurements subjects are asked to watch 10s lasting video clips showing spiders (experimental condition) or pets (dogs and cats). On a psychometric level, spider phobia will be assessed by questionnaires (SPQ, FSQ, SBQ) and behavioral assessments.

Official Title
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Neurophysiological Correlates of Exposition Therapy in Spider Phobia

Conditions
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Phobic Disorders

Intervention / Treatment
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* Behavioral: Exposure Therapy


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Spider Phobia or no fear of spiders Age between 18 and 50 normal vision (or corrected with glasses) German mother tongue or comparable knowledge Exclusion Criteria: pregnancy medication with exception of contraceptive medication acute or chronic disease that affects brain functioning (other mental diagnosis than spider phobia, cardial diseases, diabetes, kidney diseases, concussion)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Interventional Model Description: Waiting-List RCT with crossover after Treatment (Waiting-List will be treated, treated subjects will rest)
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Waiting-List<br> | Behavioral: Exposure Therapy<br>* Before the treatment, subjects will have one session of psychoeducation in which the rationale for the treatment is explained. In each therapy session subjects are exposed to 20 trials (each lasting 40s) of guided exposure by a psychotherapist. Further, 20 control trials of equal length are assessed in which subjects work with an earthworm. Each session lasts for approximately 90 minutes. During the therapy additional anxiety coping strategies (e.g., controlled breathing, attention refocusing, cognitive reappraisal) are trained. Subjects of the waiting-list will be treated in the second study phase.<br>* Other names: Psychotherapy;|
| Experimental: Treatment<br> | Behavioral: Exposure Therapy<br>* Before the treatment, subjects will have one session of psychoeducation in which the rationale for the treatment is explained. In each therapy session subjects are exposed to 20 trials (each lasting 40s) of guided exposure by a psychotherapist. Further, 20 control trials of equal length are assessed in which subjects work with an earthworm. Each session lasts for approximately 90 minutes. During the therapy additional anxiety coping strategies (e.g., controlled breathing, attention refocusing, cognitive reappraisal) are trained. Subjects of the waiting-list will be treated in the second study phase.<br>* Other names: Psychotherapy;|
| No Intervention: Healthy Controls<br>Not randomized healthy control group for comparison to normal functioning | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| fNIRS | Oxygenated and Deoxygenated Blood in the cerebral cortex will be measured with functional Near-Infrared Spectroscopy. Analysed will be Changes in Oxygenated Blood from Pre to Post-Measurement and between Control Conditions (EarthWorm) and Experimental Conditions (Working with Spiders). At Pre-Testing, the clinical population will be compared to the healthy controls. | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12); During Exposure Therapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| spider phobia questionnaire | Range SPQ: 0 to 31, high values indicate high fear of spiders | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12) | 
| Behavioral Measures | Avoidance with respect to spiders will be assessed on a behavioral scale = Spider is 5 m away (in a jar) = Patient watches pictures of spiders while the spider is 5 m away = spider is 2 m away (in a jar) = spider is 0.5 m away (in a jar) = spider is directly in front of the subject (in a jar) = spider is taken out of the jar into a larger tub = patient touches the spider with a pen = the spider is on the (covered) hand of the patient = patient touches the spider with his finger = spider walks on the hand of the patient = spider walks up the arm of the patient | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12) | 
| Peripheral Physiology | Heart rate and electromyography of the facial corrugator supercilii will be assessed | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12) | 
| EEG/EKP | Event-Related Potentials will be assessed with EEG | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12) | 
| Fear of Spiders Questionnaire | Range FSQ: 18 to 126, high values indicate high fear of spiders | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12) | 
| Spider-Phobia-Beliefs Questionnaire | Range SBQ (mean): 0 to 100%, high values indicate high maladaptive beliefs of spiders | Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (final assessment, approximately week 12) | 
| Visual analogue scales | During exposure fear, disgust and aviodance will be rated after each trial by the subject on a scale from 1 (not at all) to 9 (very much) | During each exposure session (week 1 to 5) and during EEG assessments (Before Treatment (Primary Assessment, approximately week 1), after treatment completion (secondary assessment, approximately week 6) and after study completion (approximately week 12) |