simple movements that can be voluntarily suppressed. Like tremors, they are typically back and forth movements, and most commonly occur bilaterally. They often involve fingers, wrists, or proximal portions of the upper extremities. Although, like tics, they can stem from stress or excitement, there is no underlying urge to move associated with stereotypies and these movements can be stopped with distraction. When aware of the movements, the child can also suppress them voluntarily. Stereotypies are often associated with developmental syndromes, including the autism spectrum disorders. Stereotypies are quite common in preschool-aged children and for this reason are not necessarily indicative of neurological pathology on their own. Tardive dyskinesia / tardive dystonia Tardive dyskinesia or tardive dystonia, both referred to as "TD", refers to a wide variety of involuntary stereotypical movements caused by the prolonged use of dopamine receptor-blocking agents. The most common types of these agents are antipsychotics and anti-nausea agents. The classic form of TD refers to stereotypic movements of the mouth, which resemble chewing. However, TD can also appear as other involuntary movements such as chorea, dystonia, or tics. Tics A tic can be defined as a repeated, individually recognizable, intermittent movement or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. These abnormal movements occur with intervening periods of normal movement. These movements are predictable, often triggered by stress, excitement, suggestion, or brief voluntary suppressibility. Many children say that the onset of tics can stem from the strong urge to move. Tics can be either muscular (alter normal motor function) or vocal (alter normal speech) in nature and most commonly involve the face, mouth, eyes, head, neck or shoulder muscles. Tics can also be classified as simple motor tics (a single brief stereotyped movement or movement fragment), complex motor tics (a more complex or sequential movement involving multiple muscle groups), or phonic tics (including simple, brief phonations or vocalizations). When both motor and vocal tics are present and persist for more than one year, a diagnosis of Tourette syndrome (TS) is likely. TS is an inherited neurobehavioral disorder characterized by both motor and vocal tics. Many individuals with TS may also develop obsessions, compulsions, inattention and hyperactivity. TS usually begins in childhood. Up to 5% of the population has tics, but at least 20% of boys will have developed tics at some point in their