Arm swing is reduced in idiopathic cervical dystonia.

Arm swing is typically reduced in people with Parkinsonism, and also in those with pyramidal dysfunction. We have previously observed that patients with focal arm dystonia can also have reduced arm swing. However, arm swing has not been formally studied in adult-onset primary cervical dystonia (AOPCD). We assessed arm swing in 100 consecutive patients diagnosed with AOPCD and 50 healthy controls. Reduced arm swing was more common in patients with AOPCD compared with healthy controls (55% vs. 6%, P < 0.001) and was more often abnormal on the same side as the direction of head turning (P < 0.05). Women with AOPCD had more often reduced arm swing compared with men (P = 0.002). Reduced arm swing is common in AOPCD. It may indicate segmental spread of subtle motor dysfunction or it may be a feature of dystonia per se.