They are faster than average for their age on timed tests of motor coordination, and constant tic suppression may lead to an advantage in switching between tasks because of increased inhibitory control.Learning disabilities may be present, but whether they are due to tics or comorbid conditions is controversial; older studies that reported higher rates of learning disability did not control well for the presence of comorbid conditions. There are often difficulties with handwriting, and disabilities in written expression and math are reported in those with TS plus other conditions. Causes
The exact cause of Tourettes is unknown, but it is well established that both genetic and environmental factors are involved. Genetic epidemiology studies have shown that Tourettes is highly heritable, and 10 to 100 times more likely to be found among close family members than in the general population. The exact mode of inheritance is not known; no single gene has been identified, and hundreds of genes are likely involved. Genome-wide association studies were published in 2013 and 2015 in which no finding reached a threshold for significance; a 2019 meta-analysis found only a single genome-wide significant locus on chromosome 13, but that result was not found in broader samples. Twin studies show that 50 to 77% of identical twins share a TS diagnosis, while only 10 to 23% of fraternal twins do. But not everyone who inherits the genetic vulnerability will show symptoms.
Different patterns of muscle weakness or hyperactivity can occur based on the location of the lesion, causing a multitude of neurological symptoms, including spasticity, rigidity, or dystonia.Spastic hypertonia involves uncontrollable muscle spasms, stiffening or straightening out of muscles, shock-like contractions of all or part of a group of muscles, and abnormal muscle tone. It is seen in disorders such as cerebral palsy, stroke, and spinal cord injury. Rigidity is a severe state of hypertonia where muscle resistance occurs throughout the entire range of motion of the affected joint independent of velocity. It is frequently associated with lesions of the basal ganglia. Individuals with rigidity present with stiffness, decreased range of motion and loss of motor control. Dystonic hypertonia refers to muscle resistance to passive stretching (in which a therapist gently stretches the inactive contracted muscle to a comfortable length at very low speeds of movement) and a tendency of a limb to return to a fixed involuntary (and sometimes abnormal) posture following movement. Management
Therapeutic interventions are best individualized to particular patients.Basic principles of treatment for hypertonia are to avoid noxious stimuli and provide frequent range of motion exercise. Physical interventions
Physiotherapy has been shown to be effective in controlling hypertonia through the use of stretching aimed to reduce motor neuron excitability. The aim of a physical therapy session could be to inhibit excessive tone as far as possible, give the patient a sensation of normal position and movement, and to facilitate normal movement patterns.