What causes different types of tic disorders?
Tics are irregular, uncontrollable, unwanted, and repetitive movements of muscles that can occur in any part of the body.
Movements of the limbs and other body parts are known as motor tics. Involuntary repetitive sounds, such as grunting, sniffing, or throat clearing, are called vocal tics.
Types of tics disorders
Tic disorders can usually be classified as motor, vocal, or Tourette’s syndrome, which is a combination of both.
Motor and vocal tics can be short-lived (transient) or chronic. Tourette’s is considered to be a chronic tic disorder.
The defining symptom of tic disorders is the presence of one or more tics. These tics can be classified as:
- Motor tics: These include tics, such as head and shoulder movements, blinking, jerking, banging, clicking fingers, or touching things or other people. Motor tics tend to appear before vocal tics, although this is not always the case.
- Vocal tics: These are sounds, such as coughing, throat clearing or grunting, or repeating words or phrases.
Tics can also be divided into the following categories:
- Simple tics: These are sudden and fleeting tics using few muscle groups. Examples include nose twitching, eye darting, or throat clearing.
- Complex tics: These involve coordinated movements using several muscle groups. Examples include hopping or stepping in a certain way, gesturing, or repeating words or phrases.
Tics are usually preceded by an uncomfortable urge, such as an itch or tingle. While it is possible to hold back from carrying out the tic, this requires a great deal of effort and often causes tension and stress. Relief from these sensations is experienced upon carrying out the tic.
Anxiety, anger, and fatigue may make the symptoms of a tic disorder worse.
The symptoms of tic disorders may:
- worsen with emotions, such as anxiety, excitement, anger, and fatigue
- worsen during periods of illness
- worsen with extreme temperatures
- occur during sleep
- vary over time
- vary in type and severity
- improve over time
Conditions associated with tic disorders, especially in children with TS, include: