Subgroups of idiopathic isolated cervical dystonia participants had modest but significant differences in the clinical characteristics that may represent different clinical entities or pathophysiologic subtypes, a recent study found. The Dystonia Coalition, through a consortium of 37 recruiting sites in North America, Europe, and Australia, recruited 1,477 participants with focal (60.7%) or segmental (39.3%) cervical dystonia on examination. Clinical and demographic characteristics were evaluated in terms of the body region of dystonia onset and spread. Researchers found:

• Site of dystonia onset was: (1) focal neck only (78.5%), (2) focal onset elsewhere with later segmental spread to neck (13.3%), and (3) segmental onset with initial neck involvement (8.2%).
• Frequency of spread from focal cervical to segmental dystonia (22.8%) was consistent with prior reports, but frequency of segmental onset with initial neck involvement was substantially higher than the 3% previously reported.
• Cervical dystonia with focal neck onset, more than other subtypes, was associated with spread and tremor of any type.