Tourette’s syndrome (TS) is a disorder in which individuals randomly but repeatedly exhibit stereotyped behavior (tics) of any part of the body, including the phonic (sound production) apparatus.
The first case of Tourette’s syndrome was diagnosed in 1825 by a French physician and neurologist, Georges Gilles de la Tourette. Affected individuals commonly describe an irresistible “urge” that is relieved when the tic occurs. Attempts to suppress expression of tics are usually only transiently successful. Such movements may be simple or complex and may include socially inappropriate behavior.
Incidence
The onset of TS occurs before the age of 18 years. The mean age at onset of symptoms is about 5 years, and the greatest tic severity occurs at approximately 10 years of age prevalence rates as high as 1% to 2%. It is more common in males than females.
Associated conditions
An association of TS with comorbid psychiatric disorders in pediatric patients is well described, including attention-deficit/hyperactivity disorder, obsessive-compulsive disorder (OCD), depression and anxiety.
Etiology
The etiopathology of TS is not yet clear. Genetic transmission is well documented.
Some investigators have emphasized a possible role of infections and immune response in the development of TS and other “PANDAS” (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infection) but this is not likely to be a major causative factor in most cases of TS.
The anatomic and physiologic substrate has long been believed to involve the basal ganglia and the Cortico-striato-pallido-thalamo-cortical (CSPTC) loop have revealed various abnormalities of the basal ganglia and frontal cortex.
Clinical Features
Tics are any sudden, rapid, recurrent, nonrhythmic, involuntary actions or vocalizations. There are two types:
- Motor tics
- Vocal tics
Motor Tics:
Any involuntary, rapid and sudden movements E,g.. Eye blinking, head swaying, foot tapping, shoulder shrugging, Pulling clothes, punching, kicking etc. They may be simple or complex.
Simple motor tics
- Involve single muscle or functionally related group of muscles
- Fast and brief, lasting <1 sec
- May occur in bouts of rapid succession
Complex motor tics
- Involve more muscle groups
- Sequentially and/or simultaneously produced movements
- May appear purposeful
Vocal Tics:
Any involuntary, rapid, sudden vocalizations. They are any tics that involve the larynx, tongue, throat, sinuses, or mouth. E.g. Grunting, snorting, clicking, coughing, sniffing, meaningless shouts, repeating words etc. They may be simple or complex.
Simple phonic tics- Single, meaningless sound or noise
Complex phonic tics- Linguistically meaningful utterances and verbalizations
Tics tend to worsen during stress, excitement, boredom, fatigue and ease during relaxation, sleep or when the patient is absorbrd in some activity.