Distinguishing Tics and Functional Tics Using Clinical Neurophysiological Techniques

Launched by NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE (NINDS) · Aug 21, 2025

Keywords

ClinConnect Summary

This clinical trial is studying how to tell the difference between two types of tics—those caused by neurological disorders (called organic tics) and those caused by how the brain and body send signals (called functional tics). Tics are sudden, involuntary movements or sounds that people can’t control. The goal is to better understand these differences so doctors can diagnose and treat tics more accurately.

Adults between 18 and 80 years old who have motor tics (involuntary movements) may be able to join the study, as well as healthy volunteers without tics. During the study, participants will visit the clinic for about 4 hours, which can be split over one or two days. They will avoid caffeine and alcohol before the visit. At the visit, small sensors will be placed on the skin and scalp to record muscle activity and brain waves while participants rest, have their tics monitored, and perform movements that mimic their tics. Participants will also have a blink reflex test and answer questions about their health and tics. The study team wants to learn more about how these movements happen in the body and brain, which may help improve future care for people with tics.

Gender

ALL

Eligibility criteria

• * INCLUSION CRITERIA:
• In order to be eligible to participate in this study, an individual must meet all of the following criteria:
• • Capacity to provide informed consent (self-consent)
• • Stated willingness to comply with all study procedures and availability for the duration of the study
• • Male or female, aged 18-80
• • Agreement to adhere to Lifestyle Considerations prior to and during the physiological testing visit.
• • Inclusion criteria for patients with functional tics or tics
• • - Diagnosed with functional motor tics or motor tics
• • Inclusion criteria for healthy controls
• • - Have no neurological or psychiatric disorders established by history and physical/neurological examination
• EXCLUSION CRITERIA:
• • Self-reported consumption of \>14 alcoholic drinks/week\* for a man and \>7 alcoholic drinks/week for a woman
• • Use of prescription drugs and other illicit drugs that may suppress tics such as dopamine blocking agents and antipsychotics during a certain time period prior to the
• • neurophysiological testing session.\*\*
• • Clinically significant abnormal movements on neurological examination except for tics.
• • Contraindications to EEG or EMG procedures, including skin lesions at electrode sites or hypersensitivity to electrode materials.
• • History of or current brain tumor, stroke, head trauma with loss of consciousness.
• • Epilepsy or seizures in the past 12 months.
• • Have a Baclofen pump, or have neurostimulators for pain.
• • Pregnant women
• • Self-reported current major depression or BDI-II score \>19, GAD score \> 9, or any major current psychiatric illness.
• • Presence of any metal in the eye or skull area such as a brain stimulator, shrapnel, surgical metal, clips in the brain, cochlear implants, metal fragments in the eye.
• • Presence of pacemaker, intracardiac lines, implanted pumps or stimulators.
• • Unable to comply with the requirements of the study procedures.
• • Vocal tics only.
• • Note: 1 standard alcoholic drink is 0.6 ounce (14 grams) of pure alcohol.
• • Note: The certain time period depends on different drugs used. Five half-lives will be selected. The drug is considered effectively eliminated from the body after this time period because the concentration of the drug reaches around 3% of the orininal concentration.