Electrophysiological Study of Motor Control Processes in Tourette Children

Grant Type
Clinical
Grant Year
1993
Institution Location
Foreign
Institution Organization Name
Hopital Sainte-Justine Canada
Investigators Name
Lussier, Francine, PhD

Tourette Syndrome in children has in more or less 50% of the cases, a comorbidity with Attention Deficit Hyperactivity Disorder (ADHD). This makes the ADHD occurrence 10 times more frequent than in the normal population (between 4 and 6%). Moreover, ADHD is treated with stimulants that promote the release of dopamine, whereas the neuroleptics used in the treatment of TS are dopamine antagonists. These clearly complicate the medication for both TS and ADHD. We currently lack the understanding of the physiological processes underlying these disorders that would allow us to disentangle the treatments. Our aim is to address this issue by studying three groups: children with TS and ADHD, a group with Tourette Syndrome alone and ADHD alone, and unaffected children. We will study how they control voluntary movements. Therefore, experimental paradigms using either explicit or implicit control instructions will be carried out with children of these three groups. Recordings will include event related brain potentials, muscle activity and reaction times. Recently, it has been established that before a hand movement, a negative potential, which is contra-lateral to the acting hand, can be recorded on the scalp. This potential provides an early indicator of the activation in associative brain pariatal and prefrontal areas that are related to movement preparation. It is clearly different from motor potential localized at the contra-lateral precentral area and having a maximum latency of 50 ms before muscle electrical activity. By demonstrating differences and commonalities in the physiological mechanisms underlying motor control, this may provide a major contribution to the development of more specific treatments. Event related brain potentials constitute a unique technique for visualizing functional brain activity with an exceptionally high time-resolution. It is non-invasive and painless. Thus, event-related brain potentials are adapted especially for studies comparing clinical and control groups of children. Francine Lussier, Ph.D., Centre De Recherche Hopital Sainte-Justine, Montreal, Canada Award $18,000 Tourette Association of America Inc. – Research Grant Award 1993