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Focal hand dystonia

Dystonia is a disabling movement disorder that is characterised by repetitive sustained involuntary movements that lead to abnormal postures. It may affect the entire body, or a single body part. The most common types of focal dystonia are blepharospasm and cervical dystonia (spasmodic torticollis). Focal hand dystonia is less common but improvements in recognition and awareness have changed perceptions on its prevalence. Furthermore, advances in understanding the pathophysiology of this intriguing disorder have given rise to novel therapeutic options. The most common type is when the dystonia is specific for a single task, and so this can be regarded as one of the occupational dystonias: guitarist’s, pianist’s, typist’s, and writer’s cramp, etc. The common factor is intense use of the hand in daily repetitive activity over years. In this review, we will discuss the clinical manifestations and evaluation of patients with focal hand dystonia as well as the increasing variety of treatments that are available.

Focal hand dystonia was not always considered a neurological disease. In the initial descriptions of writer’s cramp by Bell1 and Gowers2 in the 1800s, it was considered an organic illness and called “occupational neuroses”, a term attributed to disorders with a physical origin with no identifiable cause. Changes in the concept of the “neuroses”, associated with increasing interest in psychological disease around the turn of the century, resulted in grouping focal hand dystonia with other functional disorders such as hysteria. The lack of identifiable cause and the situational specificity of its presentation led to further confusion as to the origin. However, much later, in 1982, Sheehy and Marsden established the disorder as a distinct neurological entity similar to other forms of dystonia.3

Movement disorders are commonly encountered by the general neurologist and dystonias make up a respectable proportion of these patients. However, …