How Many Types of Dystonia? Pathophysiological Considerations.

Angelo Quartarone,Diane Ruge

doi:10.3389/fneur.2018.00012

Abstract

Dystonia can be seen in a number of different phenotypes that may arise from different etiologies. The pathophysiological substrate of dystonia is related to three lines of research. The first postulate a loss of inhibition which may account for the excess of movement and for the overflow phenomena. A second abnormality is sensory dysfunction which is related to the mild sensory complaints in patients with focal dystonias and may be responsible for some of the motor dysfunction. Finally, there are strong pieces of evidence from animal and human studies suggesting that alterations of synaptic plasticity characterized by a disruption of homeostatic plasticity, with a prevailing facilitation of synaptic potentiation may play a pivotal role in primary dystonia. These working hypotheses have been generalized in all form of dystonia. On the other hand, several pieces of evidence now suggest that the pathophysiology may be slightly different in the different types of dystonia. Therefore, in the present review, we would like to discuss the neural mechanisms underlying the different forms of dystonia to disentangle the different weight and role of environmental and predisposing factors.

Highlights

Dystonia is defined as a “movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both” [1]
While the interference with oscillations is likely to be immediate in the basal ganglia (BG), it takes time to erase faulty and re-establish natural motor patterns, indicative of a slow reorganization process [19]
The phenomenon observed in that paper suggests that not all parts of the “dystonic electrophysiological signature” consisting of enhanced plasticity, reduced inhibition, and impaired sensory processing are a prerequisite for the existence of clinical dystonia, but, are likely to have been important factors during the development and manifestation of dystonia as well as the alleviation of symptoms during stimulation therapy

Summary

INTRODUCTION

Dystonia is defined as a “movement disorder characterized by sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both” [1]. Dystonia may have different etiologies and present with different phenotypes [2]. Several lines of research have generalized the pathophysiology of one type of dystonia to all types [2]. There are at least three general themes that have emerged from research around dystonia. It is well known from lesion studies that dystonia can be caused by damage to multiple brain regions such as basal ganglia (BG) (often seen in imaging studies of idiopathic dystonia as well), and the thalamus, brainstem, parietal lobe, and cerebellum [3].

How Many Types of Dystonia?

Findings

FINAL CONSIDERATIONS