Patterns and types of tics vary greatly among those dealing with these disorders. Fortunately, most tic symptoms are mild. Some tic movements, such as sniffing, shoulder shrugs, and neck jerks, are termed simple and only involve one muscle group. Complex tics, on the other hand, involve movements that use multiple muscle groups with coordinated movement. Examples of complex tics are twirling or jumping while walking, and imitating someone’s actions.
Tics can occur from head to foot. They can be as mild as an occasional eye blink or severe enough to affect large muscles and knock someone from a chair. A simple motor, or movement tic can be severe in its expression; simple does not imply that the tic has less impact on an individual than a complex tic. Tics can also involve touching others or distressing self-injurious behaviors, such as slapping oneself, playing with sharp objects, or touching hot items. Vocal tics may be barely noticeable: a light cough or hum—yet some are disruptive and embarrassing: a loud shout, yelp, squeal, bark, repeating phrases just heard, or swearing (coprolalia). People often feel a sensory urge to tic that has been described by some as similar to the need to scratch an itch. After ticcing there is a sensation of released tension. The ability to recognize a sensory urge to tic increases with age; children younger than ten years are much less aware of that urge.
A large percentage of people report being able to withhold, or postpone tics for short periods, but the tics are usually “released” later. The ability to sense, or experience an urge to tic allows for this adjustment. Many people with tics become experts at disguising associated movements so they appear natural. For example, a person might appear to brush hair out of the face to make a neck jerk seem intentional. Considerable energy and attention are needed to withhold or disguise tics. Doing so can increase stress and result in physical and emotional fatigue. When children withhold tics during school, they may end up releasing them in an explosive and emotionally stressful manner at home.
Preschool children can have tics, as can elderly individuals. Childhood tics often decrease after adolescence or early adulthood.
In the United States, approximately half of children with TS also have attention deficit disorder with hyperactivity (ADHD ). Researchers also estimate that more than half of those with TS have learning problems and/or obsessive-compulsive disorder. Anxiety and panic attacks, separation anxiety, and depression are also common. Behavioral difficulties and mood swings are frequently reported, adding to the difficulty of targeting treatment.
Trichotillomania (involuntary hair-pulling) occurs at higher than average rates among those with TS. Sleep problems, bedwetting, and numerous other complaints are also frequently reported. Research suggests that patients with TS have a nearly fourfold increased occurrence of migraine headache compared with the general population.
Dealing with these coexisting conditions can be as difficult for the patient and family as the tics themselves, if not more so.
Current thought on tic symptoms
The treatment of tics has undergone dramatic change during the last century. Initially, psychologic dysfunction was thought to be the cause of tic disorders; and, therefore, the therapeutic focus was on counseling and psychotherapy, with disappointing results. Then, in the 1960s, scientists found a medical, or biological basis, for the condition, and clinicians began to prescribe medications to treat the brain and nervous system. This was a major breakthrough and resulted in improved tic control, yet it came with a caveat that remains true today. These medications are strong, often untested in children and may have serious side effects. Therefore, the severity of symptoms and the extent to which they affect quality of life determines whether drugs are advised.
No medical test exists to differentiate most tic conditions, nor can any laboratory work indicate the presence of a tic disorder or TS. At present, scientists theorize that an abnormal metabolism of the neurotransmitter dopamine is one cause. A neurotransmitter is a chemical that transmits or carries a signal from one nerve cell to another. Chemicals are released by one neuron and cross a synapse, or space, before being accepted by the next neuron. This is how nerve impulses “communicate.” It is theorized that a problem with the receiving neuron results in excess dopamine in the synapse. Other neurotransmitters, including serotonin, are also thought to be involved.
Primarily, researchers blame genetic makeup for the brain transmitter abnormalities seen with tics. Interestingly, approximately four times as many males have TS as do females, although estimates of this ratio vary. Although a strong genetic component is probable, finding a single gene responsible for tic disorders does not seem likely despite significant efforts to date. Valuable work by genetics researcher, David E. Comings, MD, author of Search for the Tourette Syndrome and Human Behavior Genes (1996), has led to a greater understanding of the interaction of tic disorders with other psychologic or neuropsychiatric conditions. Neuroimaging studies—brain mappings—of a population of patients with TS suggest abnormalities in the composition of the basal ganglia and frontal lobe white matter in the brain. The basal ganglia helps prioritize information coming to the brain and is associated with large and small motor movements. When the information being received is not filtered properly as a result of dopamine dysfunction, a range of neuropsychiatric symptoms can result. Research suggests that other areas of the brain may also play a significant role. A dysfunction of the hypothalamus with accompanying dysregulation of heat control in the body has been linked to TS.
“The difference between Tourette syndrome and other tic syndromes may be no more than semantic, especially since recent genetic evidence links Tourette syndrome with multiple and transient tics of childhood and can only be defined in retrospect.”
A Physician’s Guide to the Diagnosis of Tourette Syndrome; Tourette Syndrome Association