Introduction: Dystonia, as prolonged, involuntary muscle contraction, causes torsion, repetitive movements and abnormal body position. In so far only a part of body is affected by dystonic movement, it is the question of focal dystonia, which is called writer's cramp if the arm is involved.
Objective: The objective of the study was to present the specific clinical features of patients with task-specific dystonia, who were diagnosed, treated and followed up at the Institute of Neurology, Clinical Center of Serbia, Belgrade.
Material and methods: In the period 1995-2003, 30 patients with task-specific dystonia were treated at the Institute of Neurology, CCS, who met the adopted criteria for diagnosis. The severity of the diseases was tested by estimating the ability of patient to write the test sentence per time unit, as well as by means of scale for measuring different disabilities, ranging from 0-16 (Marsden-Fahn). Depression, anxiety and obsessiveness were tested by Beck's scale, Hamilton's depression and anxiety scale and Mousdly's obsessiveness scale. Thorough questionnaire focused on clinical details was also used. Besides descriptive statistics, data processing included analysis of variance and Kruskal-Wallis's test.
Results: Thirty patients with diagnosis of task-specific dystonia were analyzed. At the onset of the disease, mean-age was 34.1 years (SD=11.4; 13-58), while the duration of disease at the moment of the examination was 10.3 years (SD=10.6; 1-39). There were 20 males and 10 females (sex ratio 2:1). None of the patients reported any history of trauma of subsequently affected region before the development of discomforts. Twelve patients used their hands for a long time during their professions (writing, playing the instrument, type-writing, etc.). Eight patients were typists (26.6%), four were musicians (13.3%), while the rest of cases (18) had some other occupations that did not necessarily imply long-term use of hands (office worker, engineer, physician, mechanical technician, etc.). Twelve patients had simple task-specific dystonia (type I) (40%), ten cases manifested progressive diseases (type II) (33.3%), while the others suffered from dystonia that was present at rest (type III). Two patients had positive family history. DYT 1 mutation was verified in one of them. Depression, anxiety and obsessiveness were not verifed in our patients. Type of writer's cramp was not in correlation with any of the tested parameters except with the age at the onset of the disease, severity of disease according to Marsden's scale and degree of disability.