 The evaluating physician blinded will conduct a clinical examination of the patients before the injections, and 6 to 8 weeks after the injection of botulinum toxin. The pain associated with the toxin injections will be evaluated after the injections and during the follow-up visit, using the vertical indexed VAS and the Face Pain Scale. The spasticity will be evaluated on the Tardieu scale before the injections and during the follow-up visit. The duration of the botulinum toxin injections will be measured. Finally, functional objectives will be determined prior to the injections. The GAS Goal Attainment Scaling methodology will be used during the follow-up visit to determine whether these objectives have been met or not. 