- Habitual, repeated, rapid contraction of certain muscles, resulting in stereotyped individualized actions that can be voluntarily suppressed for only brief periods. They often involve the face, vocal cords, neck, and less often the extremities. Examples include repetitive throat clearing, vocalizations, sniffing, pursing the lips, and excessive blinking. Tics tend to be aggravated by emotional stress. When frequent they may interfere with speech and interpersonal relations. Conditions which feature frequent and prominent tics as a primary manifestation of disease are referred to as tic disorders.
Definition from: MeSH via Unified Medical Language System at the National Library of Medicine
- 1: Local and habitual spasmodic motion of particular muscles especially of the face: twitching.
2: A habitual usually unconscious quirk of behavior or speech.
Definition from: Merriam-Webster's Medical Dictionary by Merriam-Webster Inc.
See also Understanding Medical Terminology.