Abnormal magnetic resonance imaging T2 relaxation time asymmetries in Tourette's syndrome.

Recent imaging studies in Tourette's syndrome (TS) have reported a loss of normal asymmetry in basal ganglia volumes. Our recent report of reduced midline sagittal cross-sectional area in TS suggests that altered lateralization may be widespread throughout the TS cerebrum. We report here our analyses of cerebral asymmetries of T2 (transverse or spin-spin) relaxation times derived from multi-echo/multi-planar/spin-echo magnetic resonance images in 14 adult TS subjects and 14 matched normal control subjects. T2 relaxation times were found to be asymmetric throughout the cerebrum of normal control subjects, with differences seen between T2 times of corresponding regions of both cerebral hemispheres that were small in magnitude (2-5%) but of a high degree of statistical significance in all regions examined. Our hypothesis of altered T2 relaxation time asymmetries in TS was confirmed in a multivariate analysis of variance, with post hoc analyses suggesting that group differences were attributable to specific asymmetry differences in the TS insular cortex and frontal white matter. Exploratory analyses revealed group differences in T2 times of the amygdala and red nucleus, as well as significantly lower ferritin levels in the TS group. These findings are discussed in relation to the previous TS volumetric studies, and the tissue characteristics that might produce normal and abnormal relaxation time asymmetries are considered.

The role of central oxytocin in obsessive compulsive disorder and related normal behavior.

Oxytocin (OT) is a neurosecretory nonapeptide synthesized in hypothalamic cells, which project to widely distributed sites in the CNS as well as the neurohypophysis. Central OT affects a variety of cognitive, grooming, affiliative, sexual, and reproductive behaviors in animals. Obsessive Compulsive Disorder (OCD) includes a range of cognitive and behavioral symptoms that bear some relationship to dimensions of behavior associated with OT. Anecdotal data and a recently completed cerebrospinal fluid (CSF) study provide evidence that some forms of OCD are related to OT dysfunction. Based on these findings, we hypothesize: 1) that some forms of OCD are at the extreme end of a range of normal behaviors that are mediated by OT and related systems; and that 2) some normal cognitive, affiliative, and sexual behaviors contain elements that are similar to features of OCD. Alternative hypotheses are considered, and a series of predictions are presented concerning the relationship between central OT and the onset, course, treatment response, and response to challenge procedures seen in this form of OCD.

Severe disturbances in speech, swallowing, and gait following stereotactic infrathalamic lesions in Gilles de la Tourette's syndrome.

A 40-year-old man with severe Gilles de la Tourette's syndrome characterized by forceful self-injurious motor tics, coprolalia, and obsessive-compulsive disorder had bilateral anterior cingulotomies and bilateral infrathalamic lesions placed stereotactically during two neurosurgical procedures. During the second procedure, the patient acutely developed a marked dysarthria. Postoperatively, he manifested a severe gait disturbance with postural instability, bradykinesia, axial rigidity, micrographia, and a profound swallowing disorder. MRI showed asymmetric (left > right) low-density areas in an infrathalamic region as well as low-density areas bilaterally in the anterior cingulate gyri. Although the patient's tic and obsessive-compulsive symptoms improved, the self-injurious motor tics along with other motor and phonic tics have recurred. The patient's speech remains largely unintelligible 8 months following the last surgical procedure, and the other neurologic deficits remain unchanged.