Dystonia and Tremor.

Dystonia and tremor are common movement disorders with heterogenous presentations. Their overlap, termed "tremor in dystonia" for this review, is a common phenomenon that is classified inconsistently in practice and the literature. While the two-axis structure of the dystonia and tremor classifications clarified some aspects of tremor in dystonia, confusion and contention remain amongst clinicians. This is due not only to the varied definitions proposed over time and clinical heterogeneity, but the current lack of consensus on the underlying pathophysiology. This paper outlines the existing and proposed definitions for tremor in dystonia, clinical assessment, adjunct objective measures, and current understandings of the pathophysiology of dystonia.