Dystonia

Abstract

Dystonia is a movement disorder characterised by heterogeneous clinical manifestations that share the common denominator of abnormal and sustained muscular contractions, sometimes with tremulous features. Some forms of dystonia are focal and affect isolated body parts (e.g. torticollis, blepharospasm, oromandibular dystonia), whereas others are generalised, impacting virtually every movement; some have onset in early childhood, others become manifest later in life. Historically, it was not uncommon for cases of focal dystonia to be labelled as psychogenic. The most thoroughly investigated form of dystonia from the behavioural perspective is focal dystonia with onset in adulthood. Behavioural symptoms are frequently reported by patients with focal dystonia and can have a significant impact on health-related quality of life. Patients with cervical dystonia report a high prevalence of psychiatric disturbances, particularly anxiety and affective symptoms. Increased rates of behavioural co-morbidities have also been reported in generalised forms of dystonia, specifically obsessive-compulsive disorder in patients with myoclonus dystonia and recurrent depression in patients with genetic vulnerability to dystonia. It has been suggested that dysfunction within the cortico-limbic-striatal pathways could be a common pathophysiological substrate for the neuropsychiatric manifestations of dystonia.

Muscle tone was hypotonic at one occasion and in tonic muscle spasm at another, usually, but not exclusively, elicited upon voluntary movements

Hermann Oppenheim, About a rare spasm disease of childhood and young age (1911)