Pattern Changes and Recurrent Remissions in Cervical Dystonia: Insights from a Long-Term Treated Case

Cervical dystonia (CD) is increasingly recognized as a disorder with a dynamic clinical course rather than a fixed phenomenological profile. This report describes the long-term observation of a man with isolated CD followed for nearly 12 years from symptom onset. The course was characterized by multiple pattern changes, including a clear shift from left- to right-sided torticollis in 2019, followed by alternating and mixed dystonic patterns. Three remission phases were documented during follow-up: two prolonged periods in 2017-2018 and 2020-2021, and a further phase from March to November 2022. Over time, treatment requirements decreased from higher initial doses (500-700 U abobotulinumtoxinA and up to 130 U onabotulinumtoxinA) to lower maintenance doses of 30-50 U incobotulinumtoxinA/onabotulinumtoxinA, with longer injection intervals and no obvious documented need for dose adjustment to maintain clinical responsiveness. This case highlights the coexistence of pattern changes and recurrent remissions within a single continuously followed patient over an unusually long period. Although a treatment-related mechanism remains speculative and alternative explanations cannot be excluded, the observation underscores the value of prolonged follow-up and individualized treatment strategies in CD.