The Centers for Disease Control and Prevention (CDC) defines tics as sudden involuntary movements, sounds, or twitches.
They are different from dystonia and chorea movements in that they often follow a predictable pattern, with different tic movements regularly following each other.
Characteristically, each tic takes the same length of time every time it happens.
Doctors more commonly associate tics with Tourette's syndrome and obsessive-compulsive disorder.