MRI assessment of children with obsessive-compulsive disorder or tics associated with streptococcal infection

Area of Science:

• Neuroscience
• Pediatric Neurology
• Immunology

Background:

• Obsessive-compulsive disorder (OCD) and tic disorders can be associated with streptococcal infections.
• Basal ganglia are implicated in the pathophysiology of OCD and tic disorders.
• Previous research suggests basal ganglia abnormalities in Sydenham's chorea, a post-streptococcal autoimmune disorder.

Purpose of the Study:

• To investigate selective basal ganglia involvement in children with OCD and/or tics presumed to be streptococcus-associated.
• To determine if enlarged basal ganglia are a characteristic of this specific subgroup.

Main Methods:

• Utilized computer-assisted morphometric analysis of cerebral magnetic resonance images (MRIs).
• Compared MRI scans of 34 children with presumed streptococcus-associated OCD/tics against 82 healthy, age- and sex-matched children.
• Measured the average sizes of specific basal ganglia structures (caudate, putamen, globus pallidus) and control regions (thalamus, total cerebrum).

Main Results:

• Significantly larger average sizes of the caudate, putamen, and globus pallidus were observed in children with streptococcus-associated OCD/tics compared to controls.
• No significant differences in thalamus or total cerebrum size were found between the groups.
• The observed size differences in basal ganglia were comparable to those previously reported for Sydenham's chorea.

Conclusions:

• Findings support the existence of a distinct subgroup of children with OCD and/or tics characterized by enlarged basal ganglia.
• These results are consistent with an autoimmune response to streptococcal infection as a potential mechanism.
• The study highlights the role of basal ganglia in the pathogenesis of certain pediatric neuropsychiatric disorders.