to other primary dystonias. This indicates that oscillatory activity in these frequency bands may be involved in the pathophysiology of spasmodic torticollis. Diagnosis The most commonly used scale to rate the severity of spasmodic torticollis is the Toronto Western Spasmodic Torticollis 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 spasmodic torticollis. Classification Spasmodic torticollis 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 spasmodic torticollis: 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). Spasmodic torticollis can be further categorized by the direction and rotation of head movement. Primary Primary spasmodic torticollis is defined as having no other abnormality other than dystonic movement and occasional tremor in the neck. This type of spasmodic torticollis 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 spasmodic torticollis. 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 spasmodic torticollis. Secondary When other conditions lead to spasmodic torticollis, it is said that the spasmodic torticollis 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 spasmodic torticollis 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 spasmodic torticollis, one can note the position of