Eye Movement Disorder in Infancy: Stereotypic vs. Tic?

Paroxysmal events such as stereotypic movement disorder and provisional tic disorder are common motor behaviors in childhood; differentiating between the two is difficult, particularly in infancy. Both are transient, worsened by excitement and stress. Stereotypies are more rhythmic and predictable than tics which are sudden, rapid, jerky, motor movements that wax and wane. Additionally, stereotypic movements are often described as pleasurable. Typically, stereotypies occur at a younger age; but still, there is no developmental threshold for tics. We examined two unusual cases of a 12-month-old female presenting with stereotypic ocular movements and a 14-month-old female presenting with infantile tic-like signs.