Dystonia is associated with co-contraction of antagonist muscles and contraction of adjacent unnecessary muscles to the movement that refer to overflow.
Thus, overflow, defined as an unintentional muscle contraction, which accompanies, but is anatomically distinct from the primary voluntary or involuntary movement, is a characteristic of the disease (Ceballos-Baumann et al., 1995a; Geyer and Bressman, 2006).
A functional lesion by deep brain stimulation of the internal portion of the globus pallidus is a potential alternative treatment but remains an invasive procedure, so that other treatments are looked at (Albanese et al., 2015).
In the past years, TMS allowed to improve the understanding of the pathophysiology of dystonia by the evaluation of various cortical areas’ excitability. Multiple sessions of low-frequency repetitive transcranial magnetic stimulation in focal hand dystonia: clinical and physiological effects.
At last, F-fluorodeoxyglucose PET, which evaluates the areas of brain activity based on glucose metabolism, has shown a bilateral increased activity in the lentiform nucleus at rest in childhood onset dystonia (Eidelberg et al., 1998). Schematic representation of the basal ganglia circuitry.
Dystonias represent a heterogeneous group of movement disorders responsible for sustained muscle contraction, abnormal postures, and muscle twists. Orbicularis oculi reflex in the Wallenberg syndrome: alteration of the late reflex by lesions of the spinal tract and nucleus of the trigeminal nerve.
It can affect focal or segmental body parts or be generalized. doi: 10.1001/archneur.1970.00480200062006 Pub Med Abstract | Cross Ref Full Text | Google Scholar Kimura, J., and Lyon, L.
Patchy neuronal loss and gliosis has been rarely found in the caudate nucleus or in the putamen (especially in their dorsal parts) in idiopathic generalized dystonia (Gibb et al., 1992), or in the cerebellum in cervical dystonia (Kostić et al., 1996; Prudente et al., 2013). Positron emission tomography scanning in essential blepharospasm.
The central role of basal ganglia loop (Figure 1) in dystonia has been supported by the beneficial results of thalamotomy (Andrew et al., 1983; Vitek et al., 1998), pallidotomy (Ondo et al., 1998), or basal ganglia deep brain stimulation (Vidailhet et al., 2005; Kupsch et al., 2006; Volkmann et al., 2012) on dystonic symptoms.
Primary dystonia is the most common form of dystonia but it can also be secondary to metabolic or structural dysfunction, the consequence of a drug’s side-effect or of genetic origin. Based on lesion studies, dystonia has been regarded as a pure motor dysfunction of the basal ganglia loop.