Clinical and Imaging Correlates of Cognitive Impairment Patterns in Early Unilateral Brain Injury Associated with Sturge-Weber Syndrome

Background: Sturge-Weber syndrome (SWS) is a rare neurocutaneous disease characterized by cerebral venous malformations leading to early damage of affected brain regions. Clinical symptoms include seizures, motor and cognitive impairment. Most SWS patients have unilateral brain involvement, and previous studies reveal substantial neurological plasticity in some of them. Some children with left-hemispheric damage demonstrate, paradoxically, preserved verbal functions and reduced nonverbal functions (a “crowding” effect), suggesting contralateral functional reorganization from damaged cortical regions. We evaluated the incidence as well as clinical and imaging correlates of such functional reorganization/crowding. Methods: Forty-six patients (age: 2.5-24 years) with unilateral SWS underwent neurocognitive evaluations and magnetic resonance imaging (MRI) prospectively. Cases were stratified by hemisphere and assigned to a cognitive group: 1=normal, 2=traditional (expected deficit), 3=reorganized (contralateral deficit), and 4=global impairment (bilateral deficits). Age, IQ, seizure variables, and neuroimaging characteristics were compared across groups. Results: Evidence of functional reorganization/crowding was seen only in left-hemispheric patients (n=20, 35%; right, n=26; 0%). In left-sided cases, the global deficit group demonstrated more extensive vascular malformations (p=0.003), atrophy (p=0.003), enlarged medullary veins (p=0.017), and lower age at seizure onset (p=0.016) than the normal group. Reorganized cases demonstrated shorter epilepsy duration (p=0.02) and more variable seizure onset age compared to the global group. Conclusions: Evidence of functional reorganization, associated with crowding, in only left-sided cases suggests prioritization of verbal over non-verbal functions. Earlier and longer duration of seizures may interfere with optimal reorganization. Future studies may focus on modifying clinical characteristics that interfere with optimal reorganization of cognitive function.