Tremor in Dystonia: A Cross-sectional Study from India

Tremor is an important phenotypic motor feature in dystonia, but there is limited literature regarding its prevalence and phenomenology.

This cross-sectional study included 90 patients with adult-onset, isolated dystonia from a tertiary care movement disorder center in India. Patients were assessed for tremor in the head and in different body parts. Surface electromyography studies of tremor were recorded of the involved limb in different positions.

Tremor was present in 41 patients (45.55%) who had dystonia, including 21 of 41 patients (51.21%) with cervical dystonia, 15 of 34 (44.11%) with limb dystonia, and 5 of 15 (33.33%) with cranial dystonia. Significantly later age at presentation (47.19 ± 14.55 years vs. 40.39 ± 13.74 years; P = 0.012) and longer disease duration (5.11 ± 5.85 years vs. 2.60 ± 2.57 years; P = 0.004) were observed in patients with versus without tremor. Upper limb tremor was present in 33 patients, head tremor was present in 14, and leg tremor was present in 2. Tremor was present in 17 of 25 patients (68%) with segmental dystonia and in 6 of 9 (66.66%) with multifocal dystonia. Tremor was least frequent in patients with focal dystonia (18 of 56 patients; 32.14%).

Tremor was common (>45%) in patients with primary adult-onset dystonia. Patients who had tremor were older and had a longer duration of symptoms. Patients with segmental and multifocal dystonia had more tremor than those with focal dystonia. In contrast to some other studies, the current patients had more upper limb tremor than head tremor, and a combination of dystonic tremor and tremor associated with dystonia was more common than isolated dystonic tremor.