A tic is defined as sudden, rapid, repetitive, involuntary muscle contractions (motor tics) or vocalizations (vocal tics). They are typically brief, rarely lasting longer than one second. Examples include blinking, facial grimacing, nose twitching, or throat clearing. Tics often occur in bouts, with periods of remission or reduced tic activity in between. While tics can often be temporarily suppressed, their frequency and intensity may increase during periods of emotional change or stress.