Adult-Onset Idiopathic Cervical Dystonia

Abstract

Adult-onset idiopathic focal dystonia is the most common type of primary dystonia, and adult-onset idiopathic cervical dystonia (AOICD) is its most prevalent phenotype. AOICD is an autosomal-dominant disorder with markedly reduced penetrance; clinical expression is dependent on age, sex, and environmental exposure. Motor symptoms at presentation are poorly recognised by non-specialists, leading to long delays in diagnosis. Certain features of history and examination can help diagnose cervical dystonia. There is a relatively high prevalence of anxiety and/or depression, which adversely affects health-related quality of life. Recent studies indicate that patients with AOICD also have disordered social cognition, particularly affecting emotional sensory processing. AOICD can be treated reasonably effectively with botulinum toxin injections, given at 3-month intervals. Oral antidystonic medications are often trialled initially, but are largely ineffective. Comprehensive modern management of patients with AOICD requires recognition of presence of mood disorders, and actively treating the endogenous mood disorder with antidepressant therapy. Botulinum toxin injections alone, no matter how expertly given, will not provide optimal therapy and improved health-related quality of life without an holistic approach to patient management. Increasing evidence indicates that AOICD is a neurophysiological network disorder of GABAergic inhibition, causing a syndrome of dystonia, mood disturbance, and social cognitive dysfunction, with the superior colliculus playing a central role.