Inclusion Criteria:  Aged more than 18 years old Complicated biamniotic monochorionic twin pregnancy Indication for fetal surgery: Fetoscopy laser photocoagulation or Selective termination of pregnancy. Patient Consent Affiliation to a social security coverage  Exclusion Criteria:  No understanding of the French language Visually impaired or hard of hearing Participation in another intervention research Patient under State medical aid Psychiatric disorders (schizophrenia, schizophreniform disorders) Major neurocognitive disorders (dementias) Migraine helped a basic treatment Epilepsy with treatment Pacemaker carrier With lesions on the scalp