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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
40
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.
Department of Psychiatry and Psychotherapy, University Hospital Tuebingen
Tübingen, Baden-Wurttemberg, Germany
RECRUITINGfNIRS
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.
Time frame: 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
spider phobia questionnaire
Range SPQ: 0 to 31, high values indicate high fear of spiders
Time frame: 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 1. = Spider is 5 m away (in a jar) 2. = Patient watches pictures of spiders while the spider is 5 m away 3. = spider is 2 m away (in a jar) 4. = spider is 0.5 m away (in a jar) 5. = spider is directly in front of the subject (in a jar) 6. = spider is taken out of the jar into a larger tub 7. = patient touches the spider with a pen 8. = the spider is on the (covered) hand of the patient 9. = patient touches the spider with his finger 10. = spider walks on the hand of the patient 11. = spider walks up the arm of the patient
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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
Time frame: 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)
Time frame: 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)
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