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Echopraxia, a tic disorder is the involuntary repetition of another person’s movements. Imitation and emulation of physical and verbal actions are critical to early development. However, when these behaviors become reactions rather than a means for learning, they are considered echophenomena. Echopraxia has been observed in patients with frontal lobe damage, but the exact cause is currently unknown. Patients with Gilles de la Tourette Syndrome, Schizophrenia, and Latah exhibit echopraxia; however, the reason for the link between echopraxia and these disorders is undetermined. Echopraxia is closely related to echolalia, the involuntary repetition of another person’s words or word phrases. Although no medical treatments are available, psychological counseling may help patients who exhibit echophenomena in some cases. The effects of therapy vary depending on the initial cause of echopraxia.

Eponym

Echopraxia is sometimes grouped with echolalia, and referred to as echophenomena.

Etymology

Echopraxia, termed in 1904, is derived from Ancient Greek: "ekho" + "praxis", meaning action.

History

Echopraxia was observed in the first case of Tourette's Syndrome. Jean Marc Gaspard Itard described the original case of Marquise de Dampierre in 1825.

Signs and Symptoms

Echopraxia is typically classified by the uncontrollable mirroring of an observed action. Imitated actions are not limited to a specific type. Imitation can be divided into two types: imitative learning and automatic imitation. Imitative learning occurs when a person consciously mimics an observed action in order to learn the mechanism behind that action and perform it himself or herself. According to Jean Piaget, this is essential to the sensorimotor stage. Imitative learning continues to develop as a person ages, and is important as new skills are available to learn. For example, a person may learn to hit a nail with a hammer by watching his or her parent hammering nails. Automatic imitation on the other hand, occurs without a person's consent. Babies begin copying movements soon after birth. It is not possible to diagnose echopraxia at this age, because it is difficult to differentiate between imitative learning and automatic imitation. This normally begins diminishing around the age of 3 years old. If the imitative behavior continues to be present, it is considered echopraxia. Automatic behavior is occasionally present in healthy adults. For instance, when a person observes someone yawning, he or she immediately does the same. These behaviors are not considered echopraxia.

Causes and Pathophysiology

When learning a new action, the parietal lobe of the brain is responsible for directly observing the action and its spatial configuration. The premotor cortex of the frontal lobe encodes how that action is being conducted. A healthy brain can differentiate between seeing and doing. Damage to the frontal lobe could be responsible for combining the two and causing echopraxia.

Frontal lobe damage may affect the mirror neuron system, a group of neurons in the F5 region of the brain. These neurons fire action potentials when an action is observed, as well as when the action is being performed. They are primarily located in the inferior frontal gyrus and the inferior lobule of the parietal lobe. When an action is being observed or executed, the path begins at the occipital cortex, where the brain processes the visual input. The action then progresses to the superior temporal sulcus, which plays an important role in perception of biological movements. The parietal cortex is then able to map the action. Finally, the action passes through the inferior frontal gyrus and ends at the primary cortex. Damage to any of these components could cause echopraxia.

Diagnosis

Echopraxia not diagnosed by formal testing. It is easier to distinguish in individuals over the age of 5 years old. Because younger children frequently imitate others' actions, it is difficult to define echopraxia in them. Older individuals easily notice echopraxia, because their behaviors in relation to prior behaviors can be differentiated.

Treatment

Medical Treatments

Medical or chemical treatment is not currently available for tic disorders, including echopraxia.

Therapeutic Treatment

Therapeutic treatment has an effect on general tic disorders in some cases. If repairable problems contribute to the cause of the tic, such as family, school, or health problems, therapeutic treatment is more likely to be successful. There is evidence which supports a problem being resolved and the tic diminishing.

Stress-induced Tic Suppression

There have been instances reported where severe stress suppresses the tic. For example, Oliver Sacks has written about a surgeon and amateur pilot with severe Tourette Syndrome who was successful because his tics disappeared in the operating room and on a plane. However, this is not an effective means of treating tics as they re-appear in non-stressful situations.

Echopraxia in Neurological Disorders

The reason for the link between echopraxia and the following neurological disorders is unknown. Possible mechanisms, as follows, have been suggested.

Gilles de la Tourette Syndrome

Echophenomena is expressed in 21-46% of patients with Tourette Syndrome. These patients typically experience increased sensitivity to external stimuli, which makes them more susceptible to acquiring tics.

Schizophrenia

Some studies have shown that Schizophrenia is associated with decreased inhibition and increased arousal in the nervous system. A proposed mechanism for echopraxia in Schizophrenia is related to disinhibition, arousal, and the mirror neuron system. Dysfunction of the anterior cingulate cortex, where cognitive and motor processes converge, is common in patients with Schizophrenia. This dysfunction could cause movements to pass throughthe inferior frontal gyrus and automatically be repeated.

Latah

Echopraxia is a common characteristic in individuals affected with Latah, a condition in South Asia triggered by the startle reflex. Patients with Latah perform exaggerated actions when startled.