Objective: To determine whether children with shunted hydrocephalus show variations in regional brain tissue composition that relate to cognitive functions.
Design: Nonequivalent control group.
Patients and methods: Magnetic resonance imaging (MRI) and cognitive skills assessments were obtained on 28 children, 6 to 9 years of age, with shunted hydrocephalus and 13 normal control subjects comparable in age, gender, ethnicity, and socioeconomic status. Three consecutive MRI slices below the vertex were segmented using a fuzzy clustering algorithm to separate pixels into gray matter, white matter, and cerebrospinal fluid (CSF) in quadrants representing left and right anterior and posterior brain regions. The cognitive skills assessments included the Wechsler Intelligence Scale for Children-Revised verbal and performance IQ scores, neuropsychological composites of language and visuospatial skills, a measure of visuomotor dexterity, and 2 measures of problem-solving abilities. The MRI data were analyzed in a group x tissue x hemisphere x region analysis of variance. Spearman rho correlations were computed within the hydrocephalus group between the MRI and cognitive measures.
Results: Children with hydrocephalus showed reductions in overall gray matter percentages and corresponding increased CSF percentages that were more pronounced in posterior than anterior regions of both hemispheres. White matter percentages were reduced in children with hydrocephalus only in the left posterior quadrant. Correlations of posterior, but not anterior, CSF and gray matter percentages were significant with verbal and performance IQ scores and language, visuospatial, and visuomotor dexterity skills, but not with problem-solving abilities. Children with hydrocephalus who had proportionately greater posterior than anterior CSF percentages had significantly poorer visuomotor dexterity and visuospatial skills than did hydrocephalic children with proportionate CSF percentages.
Conclusion: Regional variations in brain tissue composition in children with shunted hydrocephalus correlate with a variety of cognitive and visuomotor functions.