Correlation between interictal cerebral glucose hypometabolism and IQ in children with epilepsy
Zhihong Tang1, Zhihong Chen2, Qiongxiang Zhai2
1Department of Pediatrics, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangdong Neuroscience Institute, China; Southern Medical University, Guangdong Province, China.
Insights
Children with epilepsy show lower IQ scores and altered brain glucose metabolism. Interictal PET scans reveal that abnormal brain metabolism correlates with reduced IQ and specific cognitive discrepancies.
Area of Science:
- Neuroscience
- Pediatric Neurology
- Medical Imaging
Background:
- Epilepsy in children is often associated with cognitive impairments.
- Understanding the relationship between brain metabolism and cognitive function is crucial for managing epilepsy.
- Existing research suggests potential links between brain glucose metabolism and intelligence quotient (IQ) in pediatric populations.
Purpose of the Study:
- To investigate the relationship between intelligence quotient (IQ) and brain glucose metabolism in children with epilepsy.
- To compare cognitive performance and brain metabolism between children with epilepsy and healthy controls.
- To explore how different patterns of brain metabolism correlate with specific IQ measures and hemispheric lateralization.
Main Methods:
- Participants included 78 children with epilepsy and 15 healthy children.
- Cognitive function was assessed using the Chinese Wechsler Intelligence Scale for Children (C-WISC), measuring verbal IQ (VIQ), performance IQ (PIQ), and full-scale IQ (FIQ).
- Brain glucose metabolism was evaluated using interictal positron emission computed tomography (PET) with 2-deoxy-2[(18)F]fluoro-d-glucose (FDG) tracer.
Main Results:
- Children with epilepsy exhibited significantly lower VIQ, PIQ, and FIQ compared to healthy children (P<0.001).
- IQ scores differed significantly across groups with normal, unifocal, and multifocal abnormal brain hypometabolism.
- The extent of abnormal brain hypometabolism showed a significant negative correlation with FIQ (rs=-0.549, P<0.001).
- Significant differences in VIQ/PIQ discrepancy scores were observed between left and right hemispheric hypometabolism subgroups (P=0.004).
Conclusions:
- Brain metabolic abnormalities in children with epilepsy are significantly correlated with reduced IQ.
- Interictal PET combined with C-WISC assessment provides a comprehensive evaluation of cognitive impairment severity and VIQ/PIQ discrepancies.
- These findings highlight the utility of integrating neuroimaging and neuropsychological testing for a deeper understanding of cognitive deficits in pediatric epilepsy.
Abstract:
The aim of this study was to understand the relationship between IQ and glucose metabolism in brain cells in a wide variety of subjects with epilepsy. The study participants were 78 children with epilepsy and 15 healthy children for comparison. All participants were administered the Chinese Wechsler Intelligence Scale for Children (C-WISC). The verbal intelligence quotient (VIQ), performance intelligence quotient (PIQ), and full-scale intelligence quotient (FIQ) were compared between children with epilepsy and typically developing children. Seventy-eight patients underwent interictal positron emission computed tomography (PET) using 2-deoxy-2[(18)F]fluoro-d-glucose (FDG) as the tracer for evaluating brain glucose metabolism. Verbal intelligence quotient, PIQ, and FIQ based on the C-WISC were significantly lower in children with epilepsy than those in the healthy comparison group (P<0.001, P=0.001, and P<0.001, respectively). The IQ of patients with normal metabolism, unifocal abnormal hypometabolism, and multifocal abnormal hypometabolism determined by PET differed significantly. The extent of the abnormal hypometabolism was negatively correlated with the FIQ (rs=-0.549, P<0.001). In patients with lateralized hypometabolism based on PET, the VIQ/PIQ discrepancy scores (|VIQ-PIQ|≥15 points) differed significantly between the left hemisphere abnormal hypometabolism and right hemisphere abnormal hypometabolism subgroups, with negative values in the left and positive values in the right subgroups (P=0.004). In conclusion, brain metabolic abnormalities are correlated with IQ, and performing interictal PET along with C-WISC can better assess the extent of severity of cognitive impairment and VIQ/PIQ discrepancy.
