and Peter Hedera2
(1)
Parkinson’s Clinic of Eastern Toronto, Toronto, ON, Canada
(2)
Department of Neurology Division of Movement Disorders, Vanderbilt University, Nashville, TN, USA
Abstract
Tics are sudden, nonrhythmic, repetitive, stereotyped motor movements that are temporarily suppressible and may resemble purposeful-like movements. This chapter reviews main clinical characteristics of ticks and their most common causes. We describe characteristic phenotypic features of conditions associated with both motor and vocal ticks, their differential diagnosis, and most useful clinical work-up. The main emphasis is on Tourette syndrome and its clinical management, including motor and non-motor presentation of this common neurologic condition.
Keywords
TicsHyperkinetic movementsTourette syndromeObsessive-compulsive disorderA tic is a sudden, nonrhythmic, repetitive, stereotyped motor movement or vocalization involving discrete muscle groups.
4.1 Classification
There are two main clinical types of tics, which include motor tics and vocal tics. Motor tics can be simple and complex. Simple motor tics can be further classified as clonic and dystonic. Similarly, vocal tics can be simple or complex.
Some of the examples of simple motor tics include eye blinking, eyebrow raising, and facial grimacing, whereas complex motor tics include head jerking and jumping. Simple vocal tics include sniffing and throat clearing, whereas complex vocal tics include coprolalia and whistling. Tics are regarded as the universal clinical sign of Tourette syndrome.
4.2 General Presentations
As mentioned above, tics may be simple or complex. Simple motor tics are short, jerk-like movements which are sudden in onset and rapid, such as clonic tics, e.g., blinking and head jerking. However, they may also be slower and cause a brief abnormal posturing, such as dystonic tics, e.g., sustained mouth opening, bruxism, and shoulder rotation.
Most of the patients with motor and phonic tics have preceding premonitory sensations such as tension or burning feeling in the eye before a blink.
Complex motor tics consist of sequenced and coordinated movements that resemble normal acts that are inappropriately intense. On the contrary, simple phonic tics normally consist of squeaking, grunting, sniffing, throat clearing, blowing, screaming, coughing, and sucking sounds. Tics can typically be volitionally suppressed, but it may require an intense mental effort. Besides temporary suppressibility, tics are also characterized by exacerbation and suggestibility with stress, fatigue, and excitement. Tics may increase while relaxing after a period of stress.
Although tics usually can be suppressed for short periods of time, the inner sensation builds up, consequently leading to a burst of tics when the patient stops suppressing them. Tics usually begin in the neck (head shaking) and face (grimacing, eye blinking). They may spread to further involve the limbs and may be accompanied by various sounds (barking, throat clearing, sniffing, words, or parts of words) and sometimes by foul utterances (coprolalia). Repeating movements (echopraxia) or sounds (echolalia) are often observed.
Simple clonic tics can resemble essential myoclonus, which makes it extremely difficult to distinguish between the two conditions. Dystonic tics should be differentiated from primary torsion dystonia. Intermittency, suppressibility, and premonitory sensations help distinguish tics from most other movement disorders.
Generally, tics start around age 5–6 years and increase in intensity, reaching its most severe period at around age 10. After age 10, there is generally a steady decline in the severity of the disorder. By the age of 18 years, about half of all patients are virtually free from tics.
4.3 Investigations
Usually no investigations are required in majority of patients with tics.
4.4 Causes
4.4.1 Tourette Syndrome
The Gilles de la Tourette syndrome, generally shortened to Tourette syndrome, is characterized by both phonic and multiple motor tics that change in character over time, with onset before 21 years of age and symptoms that wane and wax but last more than a year. It is considered the most common cause of tics.
Although the definition is a helpful criterion for research on the disorder, it excludes chronic motor tics or an onset beyond the age of 21 years. It is possible that these conditions may represent milder expressions of Tourette syndrome.
Although it was once considered a rare psychiatric condition, Tourette syndrome is now regarded as a relatively general and intricate neurologic condition. The prevalence of Tourette syndrome in adolescents is around 5 per 10,000 in males and 3 per 10,000 in females.
Several patients have a behavioral component of obsessive-compulsive or attention-deficit disorder. Tourette syndrome may also be associated with hyperactive behavior. The genetic inheritance pattern of Tourette syndrome is controversial.
In patients who have come to necropsy, no specific morphologic changes in the brain have been observed. Dopamine receptors are not increased in the striatum, but hyperinnervation with dopamine terminals has been taken into account by increased mazindol binding. Neuroimaging has displayed incoherent asymmetries in the basal ganglia, in which serum antibodies against the putamen have been found.
When tics are mild and not socially disabling, no treatment is required. However, when more severe, motor and phonic tics can sometimes be reduced with clonazepam and clonidine. Dopamine depletors and antagonists are most effective in the treatment of tics. Pimozide (Orap®) is indicated for the suppression of motor and phonic tics in patients with Tourette syndrome who have failed to respond satisfactorily to standard treatment. It is not intended as a treatment of first choice nor is it intended for the treatment of tics that are merely cosmetically troublesome. Other classic neuroleptics can be also used and the patients must be monitored for the emergence of tardive dyskinesia. Monitoring of QT interval is also important with serial electrocardiograms. Overall, dopaminergic antagonists cause the more severe complication and therefore should be used cautiously.
Patients with medically refractory tics may be considered for deep brain stimulation procedure. However, the role of surgical therapy has not been determined yet, and this approach remains experimental.
Bibliography
Bernabei M, Andreoni G, Mendez Garcia MO, et al. Automatic detection of tic activity in the Tourette Syndrome. Conf Proc IEEE Eng Med Biol Soc. 2010;2010:422–5.PubMed
Copur M, Hergüner S, Arpaci B. Tolerability of quetiapine in children and adolescents with Tourette’s syndrome. Int J Clin Pharmacol Ther. 2011;49:177–8.PubMed
Debes NM, Hansen A, Skov L, Larsson H. A functional magnetic resonance imaging study of a large clinical cohort of children with Tourette syndrome. J Child Neurol. 2011;26:560–9.PubMedCrossRef
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