Dystonia

We read with interest the article “Dystonia: Five new things” by Berman and Jinnah.1 The authors describe evidence that dystonia is a complex network disorder arising from the dysfunction of one or more parts of the brain, including the basal ganglia, thalami, cortex, cerebellum, and pontine and dentate nuclei. We would like to stress that muscle spindles and their distorted proprioceptive feedback to central processing structures also form a crucial part of the pathophysiologic network described above.2

We have demonstrated that idiopathic focal dystonias are underpinned by abnormalities in genetically determined physical properties of muscle spindles, which produce aberrant fatigue-induced proprioceptive signals.3 This genetic predisposition possibly interacts with other related genetic changes (i.e., TOR1A, THAP1) that have only partial penetrance in order to produce the dystonic phenotype.4 Moreover, it has previously been shown that, apart from its peripheral effects, botulinum toxin may also work by inducing central “cortical molding” through modulation of the afferent muscle spindle inputs.2,5 Thus, the primary abnormality in idiopathic focal dystonia may not lie exclusively in the brain. Although science has thrown some light onto the pathophysiology of dystonia, the scene is much easier to interpret if the key player is acknowledged.

Disclosures:

The authors report no disclosures.