The aim of this study is to assess feasibility, acceptability and efficacy of two VRET (Virtual Reality Exposition Therapy)session associated with either active anodal tDCS or sham tDCS on the ventromedial prefrontal cortex to decrease anxiety related to visual height intolerance

Subjects suffering from visual height intolerance are asked to go in 20 min as height as possible riding in two elevators of adjacents buildings separated by a board they have to cross at each stage.

Inclusion visit:

• Confirmation of eligibility criteria
• Written informed consent
• Completion of Acrophobia Questionnaire (AQ), Attitude towards Height Questionnaire (ATHQ), Height Interpretation Questionnaire (HIQ), Visual Height Intolerance scale(vHI), State-Trait Anxiety (STAI), Inventory and Clinical Global Impressions (CGI)
• Virtual task (10 minutes): riding in an elevator. At each level,subjects are asked to rate their Subjective Units Discomfort (SUD scale from 0 to 100).
• Assessment of basal cortisol before beginning of exposure to virtual reality (sampling saliva through a Salivette®)
• Pulse and blood pressure measurements before and after session

Session 1 (within 1 to 7 days following Inclusion Visit) and session 2 (within 48 hours following session 1):

• Randomization is made by the tDCS software (double bind).
• Equipment of subject with Vive Headset (virtual reality HTC vive), trackers and (tDCS). The subject does not see the experimental room.
• Virtual task (20 minutes): the subject has to ride in an elevator up to the next floor, cross a footbridge between 2 buildings to access the elevator on the other side and be able to climb to the next floor. At each level, the subject asked to rate their SUD. The objective is to climb as high as possible.
• The active or sham brain stimulation is applied randomly during the entire virtual task.
• Assessment of basal cortisol before and after exposure to virtual reality
• Pulse and blood pressure measurements before and after session
• After session: debriefing and explication of the subjective experience (30 minutes).

End of study visit:

• Identical to inclusion visit plus :
• acrophobia/visual height
• Completion of Simulator Sickness Questionnaire (SSQ) and Igroup Presence Questionnaire (IPQ)

Inclusion Criteria:

• Without any particular ethnic and psychosocial criteria
• Subjects with fear of heights (anxiety AQ score >45 and/or VHI score >7)
• Subjects with SUD score>50/100 assessed during first visit
• Subjects without psychiatric or addictive disorders
• Subjects without criteria of phobia according to DSM5 (Diagnostic Statistical Manual)

Exclusion Criteria:

• contraindication to tDCS (neurosurgical history, intracranial device, skin problems)
• current virtual reality intolerance
• history of psychiatric or addictive disorders
• Use of psychotropic drugs
• Use of non psychotropic treatments significantly influencing mood or level of anxiety
• Neurological pathology, locomotor disability, or sensory (vestibular, visual, auditory ...)
• pregnant or breast-feeding women