Classification of Dystonia

Abstract

Dystonia is a hyperkinetic movement disorder characterized by abnormal movement or posture caused by excessive muscle contraction. Because of its wide clinical spectrum, dystonia is often underdiagnosed or misdiagnosed. In clinical practice, dystonia could often present in association with other movement disorders. An accurate physical examination is essential to describe the correct phenomenology. To help clinicians reaching the proper diagnosis, several classifications of dystonia have been proposed. The current classification consists of axis I, clinical characteristics, and axis II, etiology. Through the application of this classification system, movement disorder specialists could attempt to correctly characterize dystonia and guide patients to the most effective treatment. The aim of this article is to describe the phenomenological spectrum of dystonia, the last approved dystonia classification, and new emerging knowledge.

Dystonia Diagnosis: Clinical Neurophysiology and Genetics

“…The MDS Task Force for the Nomenclature of Genetic Movement Disorders proposed new recommendations, whose use in research and clinical practice is strongly encouraged [ 69 ]. This new nomenclature strictly connects the prefix to the predominant phenotype and considers the causative gene rather than the locus symbols (e.g., DYT 1 is now named DYT-TOR1A) [ 4 ]. The prefix DYT is used only if dystonia is the prominent disease feature due to a pathogenetic mutation [ 69 ].…”

“…The main concept to underscore is that genetic counseling depends largely on the determination of the mode of inheritance of a specific cause of an inherited dystonia in an individual (i.e., autosomal dominant, autosomal recessive, mitochondrial, X-linked inheritance). According to the inheritance, Table 3 describes all the possible diseases [ 4 ].…”

“… Legend: OMIM code = Online Mendelian Inheritance in Man code (reproduced under the terms and conditions of the Creative Commons Attribution (CC BY) license from [ 4 ]). …”

“…The role of laboratory analysis, neuroimaging studies, neurophysiology, and genetic tests is to support the etiology definition of the disease, according to the Axis II of Dystonia classification [ 1 , 4 ].…”

Dystonia: Still a Mysterious Syndrome

“…The diagnosis of dystonia is sometimes complicated due to its many clinical manifestations, causes, and the lack of specific diagnostic examinations or simple algorithms [ 1 , 2 , 3 , 4 ]. In this Special Issue, Biase et al updated a dystonia classification algorithm based on phenomenology, which could be useful to movement disorder specialists [ 5 ]. Although recent developments in AI-based deep learning technology offer highly accurate diagnostic tools in neuroimaging [ 6 ], clinical phenomenology, mainly motor manifestations, remains the gold standard for diagnosing dystonia.…”