The spread of primary late-onset focal dystonia in a long-term follow up study

Abstract

ObjectivesTo determine spread of primary late-onset focal dystonia at a long-term follow up study. MethodsAvailable patients not lost to follow up from the initial cohort were reexamined to access course and spread of dystonia. In this prolonged follow-up (13.71±5.6 years), it was possible to contact and include 66 out of 132 consecutive patients (50%) who had been diagnosed as primary focal dystonia at the Clinic of Neurology (Belgrade) from January 1990 to January 2000. ResultsRecalculation after inclusion of the new data for 66 patients revealed that the latency from the disease onset to dystonia spreading to the first new region was 4.9±4.9 years, and to the second region 5.9±8.8 years. An average time to disease progression was 12.39±1.58, 6.34±1.55 and 15.95±1.43 for patients with torticollis, blepharospasm, and those with hand dystonia, respectively. The spread of dystonia in patients with the initial blepharospasm was faster, while patients with the writer's cramp could expect further progression even after longer periods of time. Older age at onset (p=0.061), family history (p=0.028) and the presence of tremor in the region affected by dystonia (p=0.047) were the most powerful predictors of disease spreading. The majority of spreading events occurred during the first years of the disease and they appeared to be rare in later period. ConclusionsThese findings may be valuable for prognostic information on the disorder.