Distinguishing Tics and Functional Tics Using Clinical Neurophysiological Techniques

Background: Tics are involuntary movements and vocalizations. Some tics are organic: They are related to diagnosed disorders. Sometimes tics have other causes, such as problems with how the brain and body send and receive messages. These are called functional tics. It can be difficult to tell the difference between these 2 types of tics. Doctors need to know more so they can make more accurate diagnoses. Objective: To learn more about the difference between functional and organic tics. Eligibility: Adults aged 18 to 80 years who have a tic that causes involuntary movements. Healthy volunteers with no tics are also needed. Design: Participants will have one 4-hour clinic visit. The visit may be done in 1 or 2 days. Participants will refrain from consuming alcohol or caffeine before the visit. They may have a physical exam. Participants will wear two types of sensors: Electromyography (EMG): Adhesive disks with sensors will be attached to the skin above some muscles. These disks will record electricity in the muscles as the participant moves. Electroencephalography (EEG): Sensors will be placed on the participant s scalp. The sensors may be adhered directly, or the participant may wear an electrode cap. The sensors will detect brain waves. Participants will rest while seated in a chair. Their involuntary tics will be monitored with the EMG and EEG. Then they will be asked to make movements to mimic their tics. Healthy volunteers will also rest; then they will be asked to perform movements that mimic tics. Participants will have their blink reflex tested. EMG sensors will be placed on the muscles near the eyes. Electrical pulses will be used to stimulate blinking. Participants will answer questionnaires about their tics and their health....

Study Description: The purpose of the protocol is to explore the physiological difference between patients with tics and functional tics. Objectives: Primary Objective: To determine if there are differences in cortical excitability before tics in patients with tics compared to functional tics. Secondary Objectives: N.A. Exploratory Objectives: To determine if there are differences in cortical and subcortical excitability before tics in patients with tics compared to functional tics. Endpoints: Primary Endpoint: This is a hypothesis-driven study. The primary outcome measure is the beta power of EEG signal before the tics at the electrode over the vertex. Secondary Endpoints: N.A. Other exploratory outcome measures include EEG signal power across different frequency bands and Bereitschaftspotential at various electrodes with different movements. Blink reflex and pre-pulse inhibition will also be measured in patients with tics and functional tics and healthy controls under different conditions.