Prevalence and clinical features of cervical dystonia in Parkinson's disease

This prospective study examined 301 consecutive Parkinson's disease patients and found cervical dystonia (CD) present in 9.3%, substantially higher than in the general population, with most cases developing after PD onset. CD-PD patients differed from idiopathic CD patients by being predominantly male, older, and showing milder severity with less head tremor and pain.