Brain Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy in Tourette Syndrome-Year 2

Grant Type
Grant Year
Institution Location
Institution Organization Name
University of Western Ontario Canada
Investigators Name
Nicolson, Rob, MD

There have been a number of volumetric and functional brain imaging studies that suggest abnormalities in neuronal circuits involving the cortex, the striatum and the thalamus as possible causes of Tourette Syndrome. Proton magnetic resonance spectroscopy (MRS) provides unique opportunities for the investigation of neuronal abnormalities in these regions through the measurement of compounds such as N-Acetylaspartate (NAA, a putative neuronal marker), as well as glutamate, an excitatory neurotransmitter which has been hypothesized to be involved in Tourette Syndrome. Although to our knowledge there have been no published studies of proton magnetic resonance spectroscopy in Tourette Syndrome, the pilot data from our initial MRS study (sponsored last year by the Tourette Syndrome Association) suggest an increase in glutamatergic activity in the putamen and the frontal cortex. In addition, neuronal abnormalities of the putamen have also been observed. The objective of the present study is the confirmation and extension of these findings in TS through the use of magnetic resonance imaging (MRI) and MRS. Children and adolescents with Tourette Syndrome and a control group of children without tics or other major psychiatric illness will undergo MRS. Frontal gray and white matter volumes as well as the volume of basal ganglia structures and the thalamus will be measured on magnetic resonance images using semi automated techniques. In addition, the concentration of important metabolites such as N-Acetylaspartate and glutamate will be measured in these regions using proton magnetic resonance spectroscopy. We hypothesize that patients will have reductions in frontal gray matter volumes and caudate nucleus volumes. Further, we hypothesize that patients will also have increased levels of glutamate in the striatum and the frontal cortex which may suggest excess glutamatergic activity in these areas. If these hypotheses are confirmed, our findings would further advance the knowledge of the neurobiological basis of Tourette Syndrome and may ultimately be important in determining more effective treatments for tics. Rob Nicolson, M.D., Dick Drost, Ph.D., Peter Williamson, M.D. University of Western Ontario, London, Ontario, Canada Award: $67,680 (Year 2 Award) Tourette Association of America Inc. – Research Grant Award 2004-2005