MR technique reveals structural changes in Tourette's
Magnetization transfer imaging (MTI), an off-resonance technique of MRI, has been used to visualize previously unknown alterations in the cerebral architecture of patients with Tourette's syndrome. Investigators have now found a correlation between the extent of some of the structural changes and symptom severity, according to research in BMC Neuroscience.

Kirsten Müller-Vahl, MD, from Hannover Medical School in Hannover, Germany, and colleagues used normal MRI scanning and MTI to investigate the brains of 19 Tourette's patients and 20 controls.

The researchers identified alterations in the frontal lobe of the Tourette's group that they suggest may be responsible for the pathology of the syndrome.

"Our in vivo findings, using two sensitive and unbiased techniques, support the hypothesis that alterations in frontostriatal circuitries underlie Tourette's pathology," Müller-Vahl said.

The authors said that the MTI technique has never before been applied to the study of Tourette's. It is a refinement of the nuclear MR technique and allows for the detection of changes invisible to conventional MRI scanners. Tissue alterations in comparison to controls were detected in brain areas involved in the selection, programming, initiation and control of movement.

"We suggest that Tourette's is primarily caused by a dysfunction in prefrontal cortex areas rather than the basal ganglia, as has been previously thought," the authors concluded

Tourette's syndrome is estimated to affect between 1-10 children per 1,000 and, although the severity of a person's tics tends to decline with age, as many as 1 percent of the adult population may have some form of tic disorder. Symptoms include various facial, phonic and other motor tics--propensity for involuntary swearing is relatively uncommon--only affecting about 10 percent of Tourette's patients.