Letter 1 absent eye-of-the-tiger sign 1 adult 1 atypical PKAN 1 axial dystonia 1 baclofen 1 body equilibrium 1 brain depth stimulation 1 case report 1 cervical dystonia 1 clinical article 1 clonazepam 1 cognitive defect 1 deep brain stimulation 1 diazepam 1 disease exacerbation 1 disease severity assessment 1 dystonia 1 dystonic opisthotonus 1 eye of the tiger sign genetic screening 1 globus pallidus internus 1 handwriting 1 human 1 hypokinesia 1 male 1 missense mutation 1 motor performance 1 myoclonus 1 neurodegeneration with brain iron accumulation 1