Dystonia as a network disorder: a concept in evolution

Purpose of review This survey takes into consideration the most recent advances in both human degenerative ataxias, disorders with a well established cerebellar origin, and discoveries from dystonia rodent models aimed at discussing the pathogenesis of dystonia. Recent findings One common recurrent term that emerges when describing dystonia is heterogeneity. Indeed, dystonia encompasses a wide group of hyperkinetic' movement disorders, with heterogeneous causes, classification, anatomical and physiological substrates. In addition, the clinical heterogeneity of age at onset, symptom distribution and appearance of non-motor symptoms has supported the concept of dystonia as network' disorder. Pathophysiological alterations are thought to arise from dysfunction at cortico-thalamic-basal ganglia level, whereas, more recently, a role for cerebellar pathways emerged. Results from human and animal studies thus fuel the evolving concept of the network disorder. Summary Current evidence suggests the involvement of multiple brain regions and cellular mechanisms, as part of the neural dysfunction observed at system level in dystonia.