The main objective of the study is to investigate the effect of exposure to a virtual reality session during botulinum toxin injections on injection-induced stress.

The secondary objectives are to study the effect of exposure to a virtual reality session during botulinum toxin injections, on the pain induced by the injection. And study the evolution of the effects of virtual reality with the repetition of the sessions.

Botulinum toxin injections is very frequently used in the treatment of spasticity after central neurological damage (stroke, multiple sclerosis, spinal cord injury, head trauma). The injections may be painful and the tolerance of the injections varies from one patient to another. The pain felt during the injection causes in most patients great stress during the injection.

Virtual reality is a video technique with 360 ° vision simulating the physical presence of the patient in an "existing" environment outside the hospital setting. This technique has been used in painful procedures but only one publication, in pediatrics, has shown a decrease in pain and agitation during botulinum toxin injections.

The hypothesis of this research is that an immersive virtual reality system can, in adults, reduce stress and the painful experience of botulinum toxin injections.

Inclusion Criteria:

• Adult patient, male or female, suffering from spasticity of neurological origin (multiple sclerosis, stroke, head trauma, etc.) and eligible for treatment by botulinum toxin injection
• Able to give an informed consent to participate in research
• Affiliation to Social Security.

Exclusion Criteria:

• Contraindication to virtual reality (epilepsy, schizophrenia, strabismus, amblyopia, anisometropia, local contraindication to wearing a helmet (lesion of the face or the skull)
• Major cognitive disorders
• Any medical condition deemed by the investigator to be incompatible with the research.
• Indication of sedation by MEOPA during botulinum toxin injection sessions.
• Patients who have already experienced virtual reality
• Drug treatment or medical condition that may affect heart rate variability
• Pregnant or breastfeeding women
• Patients under safeguard of justice
• Refusal of participation.

According to the provisions concerning data confidentiality that are available to those responsible for the quality control of biomedical research, all researchers with direct access to the data will take the necessary precautions to ensure the confidentiality of information (participant identification and results). All data collected will be anonymized. Our study will be continued by the investigator and a second article with the results will be published. Dissemination of the results of this study will be through peer-reviewed publications, and national and international conferences

The processing of the heart rate data will be carried out blind from the device used. Indeed, the investigator must not be aware of the device used during the session so as not to have an influence and draw hasty conclusions.