Characterized by tics (repetitive, involuntary movement or vocalization)
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.
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.
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.
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.
Tics are any sudden, rapid, recurrent, nonrhythmic, involuntary actions or vocalizations. There are two types:
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
Complex motor 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.
Diagnosis
For Tourette Syndrome (TS) to be identified, several motor tics and at least one vocal tic must be present over a period of 12 months without a break of more than 3 months.
Treatment
Multi-element management approach is recommended.
Behavior therapy- Cognitive Behavioral Interventions for Tics, including habit-reversal training, can help you monitor tics, identify premonitory urges and learn to voluntarily move in a way that’s incompatible with the tic.
Psychotherapy– In addition to helping you cope with Tourette syndrome, psychotherapy can help with accompanying problems, such as ADHD, obsessions, depression or anxiety.
Tics are rarely eradicated entirely; the goal of medication is to achieve maximal control with minimal side effects.
Dopamine receptor blockers-
They work by blocking the effects of dopamine on the brain. Dopamine is a chemical in the brain thought to be associated with tics.
e.g., haloperidol, pimozide, fluphenazine and other typical neuroleptics.
Central α 2-adrenergic receptor blockers-
It is thought to stabilise levels of a brain chemical called norepinephrine which decreases the risk of the basal ganglia misfiring and triggering tics.
e.g. clonidine
Presynaptic catecholamine-depleting agents
e.g., reserpine, tetrabenazine
Preoperative and postoperative assessment tools
Deep Brain Stimulation
DBS involves the stereotactic implantation of stimulating electrodes that are positioned within specific targets in deep forebrain structures. These electrodes are connected to an implantable pulse generator that delivers a continuous high-frequency train of electrical square waves to the target.
Some authors have targeted the thalamus, whereas others have approached the globus pallidus pars interna (GPi). The precise thalamic target has not yet been established. The most effective location for stimulation is the VL thalamus. The electrode tip (contact 0) is placed on average, 4.3 mm lateral, 4.5 mm posterior and 0.1 mm inferior to the midpoint of a line between the anterior and posterior commissures, and the trajectory at 34 degrees in the lateral plane and 26 degrees anterior in the sagittal plane. In successful cases, the reduction in tic frequency has been in the 70% to 100% range. Another target for deep brain stimulation is the Globus Pallidus internus- Gpi. Results have been comparable to those of thalamic stimulation.
Prognosis
The overall prognosis is positive. Regardless of the symptom severity, individuals with Tourette’s have a normal life span.
