Understanding Tourette Syndrome

Tourette Syndrome is a poorly understood constellation of symptoms that always includes repetitive, stereotyped, involuntary movements and vocalizations known as tics. The clinical spectrum of this condition is named in recognition of Dr. Georges Gilles de la Tourette, one of the true pioneers in the field of neurology, who in 1885 first described this condition in an 86-year-old French noblewoman.

The tics of Tourette Syndrome are classified as being either simple or complex. Simple motor tics are sudden, brief, repetitive movements that involve a limited number of muscle groups. Simple tics can include eye blinking and other vision irregularities, facial grimacing, shoulder shrugging, and head or shoulder jerking. Vocalizations might include repetitive throat-clearing, sniffing, or grunting sounds. Complex tics are distinct, coordinated patterns of movements involving several muscle groups. Complex motor tics might include facial grimacing combined with a head twist and a shoulder shrug. Other complex motor tics may actually appear purposeful, including sniffing or touching objects, hopping, jumping, bending, or twisting. Simple vocal tics may include throat-clearing, sniffing/snorting, grunting, or barking. More complex vocal tics include words or phrases. Perhaps the most dramatic and disabling tics include motor movements that result in self-harm such as punching oneself in the face or vocal tics such uttering swear words or repeating the words or phrases of others. Some tics are preceded by an urge or sensation in the affected muscle group, commonly called a premonitory urge. Some of those afflicted with Tourette syndrome will describe a need to complete a tic in a certain way or a certain number of times in order to relieve the urge or decrease the sensation.

The tics characteristic of Tourette Syndrome are often made worse with excitement or anxiety and usually appear less intense during periods of calm, focused activities. Certain physical experiences can trigger or worsen tics, for example tight collars may trigger neck tics, or hearing another person sniff or throat-clear may trigger similar sounds. Tics do not go away during sleep but are often significantly diminished.

The clinical course of Tourette Syndrome is difficult, if not impossible, to predict. The early symptoms of Tourette are almost invariably noticed in childhood, with the average age at onset being between the ages of 7 and 10. Tourette is known to occur in all ethnic groups, and males are affected about three to four times more often than females. Current estimates are that 200,000 Americans have the most severe form of Tourette syndrome, and as many as one in 100 exhibit the milder and less complex symptoms such as chronic motor or vocal tics or transient tics of childhood. Although Tourette can be a chronic condition with symptoms lasting a lifetime, most people experience their worst symptoms in their early teens, with gradual improvement occurring by the late teens and continuing into adulthood.

The exact cause of Tourette Syndrome remains unknown, although recent research points toward a complex set of abnormalities involving both certain anatomical areas of the brain (such as the basal ganglia and the frontal / prefrontal cortex) as well as to possible abnormalities in neurotransmitter (serotonin, dopamine, and norepinephrine) metabolism. In the past, the relative dearth of neural tissue taken at autopsy was a significant handicap to those neuropathologists interested in determining whether a possible structural defect could be consistently identified. However, the currently expanding neurophysiology knowledge base has greatly benefited from advancements in "functional" neuroimaging technology.

Historically the primary role of "conventional" neuroimaging studies such as Computed Tomography (CT) or Magnetic Resonance Imaging (MRI) has been to exclude other conditions that could "mimic" Tourette Syndrome. The role of "functional" neuroimaging is currently expanding our knowledge regarding the precise derangements in the internal physiology of the brain and many clinicians feel that this improvement in understanding will eventually open a path to better medical management of this syndrome.

Physiologic imaging is a relatively new field that uses special "tracers" such as mildly radioactive forms of glucose or potassium to "see" the actual uptake and metabolism of those substances. In a recent article published in the Journal of Child Neurology, Frey and Albin review how the "current state of the art" in physiologic neuroimaging is opening new doors of understanding to the combined chemical and anatomic factors that may be at play in Tourette.

Noting that the use of dopamine antagonists (drugs that inhibit or counteract the neurotransmitter dopamine) has been shown to decrease the severity of Tourette-related tics, the authors devoted their attention to the analysis of tracer uptake in dopamine-producing as well as dopamine receptor areas of the brain. The results seemed to indicate that some mechanism has altered the production and distribution of dopamine in Tourette Syndrome. Unfortunately, these findings have not been consistently reproduced by other investigators. The authors speculate that this may be due to minor variations in brain anatomy and function that are difficult to accurately define by current technology.

For the immediate future, the focus on treatment of Tourette Syndrome will be devoted to symptom management and treatment of any existing "co-morbidity conditions" (conditions that are present but not directly related to Tourette). According to information provided by the Tourette Syndrome Association, co-morbidities commonly present with Tourette include attention deficit and hyperactivity disorders, low self-esteem, and social rejection by peers. These conditions obviously share commonalities and interventions will have an impact in more than the "target" area. Close communication of plans and goals between teacher, therapist, patient and the patient's family is mandatory.

In addition to "conventional" treatment of Tourette Syndrome, considerable discussion has appeared in the non-medical press regarding the potential of Deep Brain Stimulation (DBS) as a possible option in the management of this condition. DBS was first introduced as a treatment for the musculoskeletal symptoms of Parkinson's Disease and it was hoped that it would be of benefit in Tourette Syndrome. Unfortunately, DBS has failed to demonstrate an acceptable "risk to reward" relationship and has been relegated to treatment of only the most severe cases of Tourette Syndrome.

As a reminder, when using the Internet to obtain information on Tourette Syndrome or any other medical condition always consider the reliability and impartiality of the source.

References

The National Institutes of Health and the National Institute for Neurologic Disorders: Tourette Syndrome Fact Sheet (2006).

The Tourette Syndrome Association web site carries more detailed information than can be provided in a posting such as this

James F. Leckman; Michael H. Bloc;

Lawrence
Scahill; and Robert A. King:Tourette Syndrome: The Self Under Siege, J Child Neurol 2006; 21(8): 642-649.

Kirk A. Frey and Roger L. Albin: Neuroimaging ofTourette Syndrome, J Child Neurol 2006; 21(8):672-677.

A well written and well researched review of the treatment of Tourette Syndrome can be found at the Treatment of Tourette Syndrome page at Wikipedia

Dislcaimer

The information presented in this article and its included links is of an informational nature only and is not intended as a recommendation of any changes in the reader's health care program. Before making any changes in diet, medications, or other treatments the reader is strongly advised to consult with their health care provider.