Tremor in Writer’s Cramp Patients: A Retrospective Study

Abstract

Background: Tremor is one of the important motor phenotypes of dystonia, however, there is a lacuna in the literature regarding the occurrence of tremor in task-specific dystonia such as writer’s cramp (WC). Aims: To delineate the demographic and clinical characteristics of tremor in WC patients. Methods: This is a detailed chart review of 105 patients of WC who were classified as WC with dystonic action tremor (WCT+) (n = 39; 37.1%) and WC without tremor (WCT-) (n = 66; 53.9%). Results: The mean age of patients was 41.10 ± 14.02 years in the WCT + group and 36.40 ± 14.66 years in the WCT-group. Males were more commonly affected (94.9% in WCT+ and 84.8% in WCT-). The mean duration of disease was significantly higher in WCT + as compared to WCT- (4.16 ± 4.48 years vs. 2.57 ± 2.81 years, p = 0.024). One-third of our patients (29.52%; n = 31) were students but, and the majority of them were classified as WCT- (80.64%, n = 25, p = 0.01). However, tremor was present in all the three doctors in our cohort with WC (p = 0.03). The motor overflow to the elbow and shoulder was significantly associated with the presence of tremor (46.1% of WCT + vs. 15.2% of WCT-patients, p = 0.001). Statistically, there were no significant differences between WCT+ and WCT-patients regarding the presence of complex WC (dystonia during other activities as well) (p = 0.976), mirror dystonia (p = 0.211), and finger flexion/extension abnormalities (p = 0.111). Conclusion: The presence of tremor in WC was associated with a longer duration of disease and the presence of motor overflow.