Definition of focal dystonia
Focal dystonias identify alterations of voluntary musculature typical of adulthood: spasms, contractions and stiffening of some muscle groups, and again abnormal and abnormal postures, torsions and repetitive movements of some body regions, describe the pathological picture of dystonia. In particular, the focal ones are characterized by quite prolonged movements, arrhythmics, up to degenerate causing real fixed and immobile positions. The affected subject tends to worsen the condition by exerting an antagonistic action at the level of the voluntary musculature, in an attempt to restore a correct position: in doing so, unfortunately, the condition sometimes worsens, deforming the abnormal posture even more heavily and making it sadly bizarre.
Classification
As we have seen, the onset of focal dystonias is emblematic of adulthood and, in most cases, the disease does not degenerate with the passage of time (unlike, for example, dystonic infantile forms), therefore it tends to remain confined to the primitively affected site.
Among the most famous focal dystonias, we recall:
- Cervical focal dystonia
- Blepharospasm
- Focal laryngeal dystonia
- Focal dystonia of the upper limb (eg. Cramp of the scribe and dystonia of the musicians)
Cervical focal dystonia
Cervical dystonia, also known as spasmodic torticollis, is the most frequent form of voluntary muscular changes in adulthood. It is a full-fledged syndrome, in which the affected subject has evident involuntary spasms at the level of the neck musculature: these contractions are responsible for the continuous inclinations, bending and swirling of the head. Cervical pain is acute and penetrating, sometimes invalidated: in fact, among the possible serious complications, any degenerative forms affecting the medullary and cervical spine should not be underestimated.
Those most at risk are between the ages of 40 and 60, and affects 10 subjects per million healthy individuals.
A correlation between cervical focal dystonia and some pathologies, including Wilson's disease and Parkinson's disease, was recorded in some affected individuals; sometimes, focal dystonia comes from the administration of some pharmacological specialties, such as neuroleptic substances (these drugs are involved in the creation of dyskinesias in general). Many patients suffering from this dystonic focal form, also present generalized tremor, considered a constitutive element of the disease itself.
Blepharospasm
After cervical focal dystonia, blepharospasm is the most common focal dystonia; the disease affects the face, especially the upper part, and it is not uncommon for blepharospasm to be accompanied by other movement disorders. Kinetic disorder is characterized by muscle contractions and spasms that mainly involve the eyelids; sometimes, the disorder is so severe as to cause functional blindness. The patient is not able to control the movements caused by blepharospasm: the disorder begins with " excessive winking" [www.distonia.it], and then degenerates into rapid, repeated and long-lasting spasms. The diagnosis must be precise and careful since, at first glance, blepharospasm could be mistaken, mistakenly, for tic.
Botulinum toxin therapy could prove useful for resolving blepharospasm.
Focal laryngeal dystonia
A peculiar kinetic disorder of the fifty-year-olds, the focal laryngeal dystonia represents 17% of all the various dystonic forms and affects, in prevalence, the female sex. There are three forms of focal laryngeal dystonia:
- Laryngeal screeching
- Spasmodic addiction dysphonia
- Dysphonia abductory
Focal dystonia of the upper limb
They are mostly focal dystonias related to particular activities (eg playing, writing, etc.); however, there is no lack of focal dystonia of the non-action-specific upper limb, ie not connected to secondary activities. The scribe's cramp represents the most frequent action-specific form, circumscribed at the level of the muscles of the hand, the wrist and sometimes the forearm.
The contractions and spasms of the muscles of the hand, established during writing, can generate an incorrect way of holding the pen inevitably accompanied by a marked alteration of the spelling, which is increasingly difficult to understand.
The use of hand braces (used in the past) in order to remedy the scribe's cramp and modulate the posture of the hand during writing, has not reported many advantages in the symptomatological profile. Botulinum toxin is the therapeutic option of excellence, partially or totally decisive, to remedy this focal dystonia.
Among the dystonia of the upper limb there is also the dystonia of the musicians, responsible for the progressive and inevitable shrinking of the fingers, which prevents them from playing musical instruments (eg piano); once again, the infiltration of botulinum toxin into the muscles affected by focal dystonia is particularly effective.
