The role of the thalamus in neuro-cognitive dysfunction in early unilateral hemispheric injury: A multimodality imaging study of children with Sturge–Weber syndrome

Abstract

Background-Sturge-Weber syndrome (SWS) with unilateral hemispheric involvement is a clinical model of early-onset, chronic, often progressive hemispheric injury, resulting in variable neuro-cognitive impairment.Aims-To evaluate if abnormal diffusion and metabolism of the thalamus, a central relay station with extensive cortical connections, may serve as a simple imaging marker of neuro-cognitive dysfunction in SWS.Methods-We obtained both diffusion tensor imaging and FDG PET in 20 children (11 girls; age range: 3 years to 12.4 years) with unilateral SWS. Diffusion parameters as well as FDG uptake were measured in thalami, compared to normal control values, and correlated with the extent of cortical hypometabolism, deep venous abnormalities and cognitive (IQ) as well as fine motor functions.Results-Children with SWS had significantly higher thalamic glucose metabolic asymmetry than controls (p=0.001). Thalamic metabolic asymmetries correlated positively with the asymmetry of thalamic diffusivity (p=0.001) and also with the extent of cortical hypometabolism (p<0.001). Severe thalamic asymmetries of glucose metabolism and diffusion were strong predictors of low IQ (metabolism: p=0.002; diffusivity: p=0.01), even after controlling for age and extent of cortical glucose hypometabolism in children with left hemispheric involvement. Ipsilateral thalamic glucose hypometabolism was also associated with impairment of fine motor functions (p=0.002).Conclusions-Both diffusion and glucose metabolic abnormalities of the thalamus are closely related to cognitive functions, independent of age and cortical metabolic abnormalities, in children

Updates and future horizons on the understanding, diagnosis, and treatment of Sturge–Weber syndrome brain involvement

“…44 Thalamic diffusion abnormalities have been strongly correlated with IQ measures. 45 Diffusion tensor imaging can provide further information by allowing the study of white matter tract integrity and enabling the detection of early changes in specific cerebral pathways (such as the corticospinal tract) prior to the onset of neurological symptoms. 46 In one case, transient abnormal diffusion was identified concurrent with repeated complex partial seizures.…”

Brain damage and IQ in unilateral Sturge–Weber syndrome: Support for a “fresh start” hypothesis

“…The effect of thalamic hypometabolism on cognitive functions has been reported in a separate study. [20] …”

Predictors of Cognitive Functions in Children With Sturge–Weber Syndrome: A Longitudinal Study

“…In a quantitative MRI study of children with unilateral SWS, decreased white matter volume in the affected hemisphere was associated with impaired cognitive functions 10 . Cortical and thalamic hypometabolism, measured by 2-[ 18 F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET), was also associated with poor cognitive functions 11,12 . Our group has reported surprisingly preserved cognitive functions (IQ) in a subset of children with SWS and early, extensive unilateral hemispheric damage (corresponding to severe hypometabolism on PET) 12,13 ; such children likely underwent early, effective functional reorganization in the unaffected hemisphere due to extensive unilateral damage.…”