Blepharospasm and oromandibular dystonia (Meige’s syndrome)
It is characterized by the appearance of dystonic spasms of the orofacial musculature. Blepharospasm predominates, either isolated or associated with spasms of involuntary opening or closing of the mouth, protrusion of the tongue and retraction of the angles of the mouth. Blepharospasm is manifested by involuntary spasms of eye closure that interfere with vision and variably hinder activities such as reading, watching television or driving. The spasms and resulting functional blindness are often disabling from an occupational and social point of view. In patients with prominent oromandibular dystonia there may be dysarthria and great difficulty in chewing and swallowing. The spasms are aggravated by activities such as talking, walking, or reading and disappear during sleep; they are often mistakenly labeled psychogenic.
Cervical dystonia (spasmodic torticollis)
In this focal dystonia, dystonic movements and postures affect the neck musculature, especially the sternocleidomastoid, trapezius and splenius muscles, leading to a constant deviation of the head to one side (torticollis), often accompanied by dystonic cervical spasms and also frequently by elevation of one shoulder. The tonic deviation of the head can be directed, although more rarely, backwards (retrocollis) or forwards (antecollis). The disease is more common in females (2:1), starts between 39 and 50 years of age and follows a variable course. It often progresses during the first few years to leave the patient with a significant degree of physical disability. There is often cervical tremor. It is not uncommon to observe also a postural tremor of the hands. Spontaneous remissions may occur in the first years in 10% of cases.
Laryngeal dystonia (spasmodic dysphonia)
The dystonia may be localized in the laryngeal musculature and cause uncontrollable spasms of vocal cord closure (adduction spasmodic dysphonia resulting in choppy, halting, strangled-like speech). Rarely, dystonic spasms involve the posterior cricoarytenoid muscles, resulting in a whispering, hypophonic voice (abduction spasmodic dysphonia). Many patients affected by spasmodic dysphonia also have a laryngeal tremor and it is not uncommon for laryngeal dystonia to occur in patients with orofacial dystonia. In the initial stages, dysphonia occurs with speaking, but is not evident with singing and it is not uncommon for these patients to be labeled, unfortunately, as suffering from psychogenic dysphonia. Botulinum toxin injection into the overactive laryngeal musculature is the only effective treatment for this type of focal dystonia.
Scribe’s cramp
The most common focal arm dystonia is the so-called scribe’s cramp. The patient with this syndrome has difficulty writing because the pressure exerted on the pencil is exaggerated or because abnormal movements of the fingers, such as hyperextension of the fingers, prevent the patient from grasping a pencil correctly. The wrist may hyperextend or adopt forced supination or pronation postures. Writing becomes laborious due to excessive muscle contraction and jerking of the arm and is accompanied by a feeling of tension and discomfort and sometimes pain. Often the patient is forced to stop writing soon after starting. Sometimes a discreet pressure on the forearm with the contralateral hand improves writing.
Classically, the patient is able to write on a blackboard. In many patients, the writing cramp is a dystonia strictly specific to the task of writing. Other patients develop limb dystonia during manual tasks such as using a screwdriver, sewing or painting. Drug treatment is almost always ineffective and many patients are forced to learn to write with the sound hand. It may be helpful to use very thick pencils or even specifically designed writing instruments.