TorticollisDystoniaNeck MusclesDystonia Musculorum DeformansDystonic DisordersSpasmAnti-Dyskinesia AgentsVestibular Function TestsElectronystagmographyBotulinum ToxinsRetropharyngeal AbscessBlepharospasmOcular Motility DisordersAtlanto-Axial JointHead MovementsRelaxationTorsion AbnormalitySerbiaBotulinum Toxins, Type AVestibular NerveInjections, IntramuscularOphthalmologic Surgical Procedures