Correlating clinical course with baseline subcortical shape in provisional tic disorder

Area of Science:

• Neuroscience
• Developmental Neuroscience
• Pediatric Neurology

Background:

• Tic disorders, including Tourette Syndrome (TS), affect children and adolescents.
• Research on early-stage tic disorders (less than 9 months duration) is limited.
• Understanding neurobiological underpinnings of tic disorder onset and progression is crucial.

Purpose of the Study:

• To investigate the relationship between baseline subcortical nuclei shape and volume and tic disorder diagnosis in children.
• To identify potential neuroimaging biomarkers for predicting tic symptom outcomes.
• To explore differences in subcortical structures between children with new-onset tics, chronic tic disorders, and healthy controls.

Main Methods:

• 187 children (88 new-onset tics [NT], 39 Tourette Syndrome [TS], 60 healthy controls [HC]) underwent baseline and 12-month follow-up assessments.
• T1-weighted MRI scans were used to generate subcortical surface maps via FreeSurfer-initialized large deformation diffeomorphic metric mapping.
• Linear regression models correlated baseline structural features with 12-month tic symptom severity (Total Tic Score).

Main Results:

• The NT group exhibited a larger right hippocampus compared to HC.
• Distinct patterns of putamen inward and thalamus outward deformation were observed in the NT group versus controls.
• Larger baseline pallidum and thalamus volumes correlated with less improvement in tic symptoms at follow-up.

Conclusions:

• Subcortical nuclei shape and volume differences at baseline may serve as prognostic biomarkers for tic disorders.
• These findings highlight the potential of neuroimaging to predict tic disorder outcomes in children.
• Early identification of structural variations could inform targeted interventions for pediatric tic disorders.