The most commonly used scale to rate the severity of<unk>  is the Toronto Western<unk>  Rating Scale (TWSTRS). It has been shown that this rating system has widespread acceptance for use in clinical trials, and has been shown to have “good interobserver reliability.” There are three scales in the TWSTRS: torticollis severity scale, disability scale, and pain scale. These scales are used to represent the severity, the pain, and the general lifestyle of<unk> . Classification<unk>  is a form of focal dystonia, a neuromuscular disorder that consists of sustained muscle contractions causing repetitive and twisting movements and abnormal postures in a single body region. There are two main ways to categorize<unk> : age of onset, and cause. The disorder is categorized as early onset if the patient is diagnosed before the age of 27, and late onset thereafter. The causes are categorized as either primary (idiopathic) or secondary (symptomatic).<unk>  can be further categorized by the direction and rotation of head movement. Primary Primary<unk>  is defined as having no other abnormality other than dystonic movement and occasional tremor in the neck. This type of<unk>  is usually inherited. Studies have shown that the DYT7 locus on chromosome 18p in a German family and the DYT13 locus on chromosome 1p36 in an Italian family is associated with<unk> . The inheritance for both loci is autosomal dominant. These loci are all autosomal dominantly inherited with reduced penetrance. Although these loci have been found, it is still not clear the extent of influence the loci have on<unk> . Secondary When other conditions lead to<unk> , it is said that the<unk>  is secondary. A variety of conditions can cause brain injury, from external factors to diseases. These conditions are listed below: * Central nervous system tumor * Central pontine myelinolysis * Cerebrovascular diseases * Drug induced * Infectious or post infectious encephalopathies * Kernicterus * Metabolic * Paraneoplastic syndromes * Perinatal (during birth) cerebral injury * Peripheral or central trauma * Toxins Secondary<unk>  is diagnosed when any of the following are present: history of exogenous insult or exposure, neurological abnormalities other than dystonia, abnormalities on brain imaging, particularly in the basal ganglia. Head positions To further classify<unk> , one can note the position of the head. * Torticollis is the horizontal turning (rotational collis) of the head, and uses the ipsilateral splenius, and contralateral sternocleidomastoid muscles. This is the "chin-to-shoulder" version. * Laterocollis is the tilting of the head from side to side. This is the "ear-to-shoulder" version. This involves many more muscles: ipsilateral sternocleidomastoid, ipsilateral splenius, ipsilateral scalene complex, ipsilateral levator scapulae, and ipsilateral posterior paravertebrals. * The flexion of the neck (head tilts forwards) is anterocollis. This is the "chin-to-chest" version and is the most difficult version to address. This movement utilizes the bilateral sternocleidomastoid, bilateral scalene complex, bilateral submental complex. * Retrocollis is the extension of the neck (head tilts back) and uses the following muscles for movement: bilateral splenius, bilateral upper trapezius, bilateral deep posterior paravertebrals. This is the "chin-in-the-air" version. A combination of these head positions is common; many patients experience turning and tilting actions of the head.
Spasmodic torticollis
Torticollis
Dysbarism
Superior oblique myokymia
Pseudostrabismus
Benign paroxysmal torticollis
Hemifacial spasm
Misophonia