Definition
A tic is defined as a movement or vocalization that is sudden, rapid, recurring, non-rhythmic and stereotyped. It is of varying intensity and viewed by the affected person as uncontrollable.
Tics mostly occur in the upper part of the body.
Motor and vocal tics are referred to as “simple” when there is a contraction of a single group of muscles and “complex” when there is a coordinated contraction of several muscle groups.
Complex tics may comprise a sequence of movements (e.g., an exaggerated wink of the eyelid may lead to a contraction of the cheek muscles).
Complex tics belong to the category of habit disorders, such as trichotillomania, bruxism, dermatillomania or onychophagia.
Examples
The following table summarizes the most frequently observed tics.
| TIC |
MOTOR |
VOCAL |
| SIMPLE |
blinking/rolling the eyes
contracting the cheek/mouth
jerking the neck
blinking/rolling the eyes
contracting the cheek/mouth
jerking the neck
shrugging the shoulders
facial grimacing
jolting the head (back/side)
cracking the joints
bending over / stretching |
coughing
moaning
clucking the tongue
sniffling
clearing the throat
yelping
growling
shouting
|
| COMPLEX |
kicking
pulling at one’s clothes
brushing hair out the eyes
hopping or shuffling
touching/drumming/tapping the feet
scratching/pinching/hitting oneself
copropraxia
echokinesis |
spitting
whistling
burping
sniffing/breathing loudly
grinding the teeth
palilalia
echolalia
coprolalia |
Recurring involuntary somatic sensations, such as feelings of heat, pressure or itching focused on a muscle, are known as sensory tics. Sensory tics create a feeling of tension in the muscles and are often reported to be an advance warning of a tic.
Incidence
Generally, transient tics are distinguished from chronic tics and Tourette’s syndrome. The various tic disorders are identified on the basis of their duration, type and the age at which they begin.
The incidence of chronic tics is unknown, but it is estimated to range from 5% to 10% of the population. The incidence of Tourette’s syndrome in adults is around 0.1% to 1%.
Clinical Picture
The location, frequency, complexity, number and severity of tics vary by individual and throughout the life of the affected person.
Often, tics increase when the affected individual has to deal with greater than normal levels of:
- anxiety, stress, excitement, frustration, boredom or fatigue.
In certain cases, tics decrease during a period of:
- sleep, relaxation or concentration.
It is possible to control tics for a certain amount of time, ranging from a few minutes to an entire day. For example, many tics disappear while the affected person is concentrating. When tics are held back, muscle tension increases, and this tension has to be released at some point. For some, returning home is associated with a significant manifestation of tics: doing so allows them the freedom to relax the muscle tension that has been maintained throughout the day.