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Tic Disorders
Clinical Vignette
A 9-year-old boy presented to the neurology clinic with 1 year of excessive eye blinking. He was accompanied by his parents. His past medical history was unremarkable; he was born at term and reached all developmental milestones appropriately. Schoolwork has been average; he frequently loses pencils and articles of clothing. He has difficulty finishing his homework. During the past year, his parents have noticed a significant increase in his eye blinking and mention that he grimaces often. The patient is aware of the blinking and has been told by his classmates that he “squints” and “makes funny faces.” He is embarrassed by the movements. His neurologic exam was notable for eye blinking, sniffing, nose wrinkling, and contraction of the platysma. He was able to suppress the movements volitionally. He was prescribed guanfacine. After 8 weeks, he returned to the office with his parents. He reported lessening of his tics. His parents felt he was performing better in school.
Phenomenology and Classification
Tics are sudden, relatively quick, stereotyped movements (motor tics) or sounds (phonic tics) that are repeated at irregular intervals. Tics are often preceded by a premonitory urge or inner sensory stimulus and can be suppressed at will. Therefore they are referred to as semivoluntary, or unvoluntary, movements.
Tics are categorized as simple or complex ( Box 34.1 ). Simple motor tics involve only one group of muscles and are characterized by quick, jerklike movements. Usually they are abrupt in onset and brief (clonic tics), but they can also be slower and sustained (dystonic tics). Examples of simple motor tics include eye blinking, nose twitching, and shoulder shrugging. Simple phonic tics include sniffing, throat clearing, and grunting. Complex motor tics are sequenced and coordinated movements that can resemble gestures or fragments of normal behavior (e.g., kicking, jumping) and, rarely, inappropriate behavior (e.g., showing the middle finger). Complex phonic tics have a semantic basis, including words, parts of words, and obscene words (coprolalia).
Box 34.1
Tic Types—Examples
Simple Motor
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Eye blinking
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Nose twitching
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Head jerking
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Shoulder shrugging
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Tensing of abdominal muscles
Simple Vocal
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Sniffing
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Grunting
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Throat clearing
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Screaming
Complex Motor
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Touching
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Throwing
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Hitting
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Jumping
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Obscene gestures (copropraxia)
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