Brain Activation in Vocal and Motor Tics

Overview

This study will investigate the brain areas that are activated by vocal and motor tics in patients with Tourette's syndrome and other tic disorders. Tics are involuntary repetitive movements similar to voluntary movements. They may be simple, involving only a few muscles or simple sounds, or complex, involving several groups of muscles in orchestrated bouts. This study will involve only simple motor tics, such as eye blinking, nose wrinkling, facial grimacing and abdominal tensing, and simple vocal tics, such as throat clearing, sniffing and snorting. Healthy normal volunteers and patients between 14 and 65 years of age with simple motor or vocal tics may be eligible for this study. Participants will have a brief medical history and physical examination and magnetic resonance imaging (MRI) of the brain. MRI uses a magnetic field and radio waves to produce images. For the procedure, the subject lies on a table that is moved into a cylindrical chamber containing a strong magnet. Earplugs are worn to muffle the loud thumping sounds made by electrical switching of the radio frequency circuits and protect against temporary hearing impairment. During the scan, normal volunteers will be asked to make simple movements or sounds designed to imitate tics, such as raising eyebrows, blinking or coughing. Patients with tic disorders will have two parts to the scanning session. First they will relax and allow tics to occur spontaneously, then they will be asked to imitate a specific tic when there is no urge to tic. Patients and healthy subjects will have electromyography (EMG) to record the timing of the voluntary movements and tics. For this procedure, several pairs of small, saucer-like electrodes are attached to the skin with a gel or paste. Electric signals from the electrodes are amplified and recorded on a computer. A microphone may be placed near patients to record any vocal tics. A video camera may also be used to record the tics.

The purpose of this study is to determine the areas of the brain responsible for motor tics in patients with tic disorders including Tourette's Syndrome and Chronic Motor or Vocal Tic Disorder. Previous studies have been done looking at brain activity during tics using electroencephalography (EEG) and positron emission tomography (PET). 16 adult patients with DSM-IV-TR (American Psychiatric Association 2000) diagnosis of a tic disorder and frequent tics will be studied. We will utilize blood oxygenation level dependent functional magnetic resonance imaging (BOLD fMRI) on patients with tics while they are experiencing spontaneous tics and while they are voluntarily imitating those tics. The differential activation between the tics and the voluntary movements may shed light on the regions of the brain responsible for generation of tics.