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.