Tic is the term used for sudden, rapid, repetitive, involuntary muscle contractions (motor tics) and sounds (phonic tics). They are very brief, rarely lasting longer than a second. Examples include eye blinking, other facial muscle contractions, nose twitching, and throat clearing. Tics often come in bouts, with periods in between when tics are absent. Tics, which can be suppressed briefly, may increase with emotional changes and stress.