Prognostic value of brain abnormalities for cognitive functioning in cerebral palsy: A prospective cohort study

Abstract

Introduction: Brain abnormalities in cerebral palsy (CP) are known to relate to motor outcome; however, their association with cognitive functioning is less clear.

Aim of the study: 1) To investigate the prognostic value of brain abnormalities for cognitive functioning; 2) To explore the added value of prognostic variables across ICF domains: motor function, epilepsy, gestational age, birthweight and educational level of the parents.

Methods: We retrospectively analyzed brain MRI scans of 75 children with CP (GMFCS level I-V, 36% born preterm), as part of a longitudinal study. MRI classification: qualitative classification of brain abnormality pattern and semi-quantitative grading of the extent of damage. Cognitive functioning, measured as non-verbal intelligent quotient (IQ), was dichotomized into 'impaired cognition' (IQ ≤ 70) and 'normal' (IQ > 70). Multivariable logistic regression produced odds ratios (OR) with 95% confidence interval (C.I.) of risk factors for impaired cognition.

Results: Overall, 27% of the tested participants had a non-verbal IQ below 70 and 36% of the participants was classified as 'having impaired cognition'. At a young age, a higher degree of white matter damage (OR 1.6, 95% C.I. 0.97-2.67) and a more severe GMFCS level (OR 3.2, 95% C.I. 1.70-5.98) are risk factors for impaired cognition at school-age (4-7 years of age). This model correctly predicts 89% of the cases. Brain damage alone predicts the presence of impaired cognition in 71% of the cases.

Interpretation: Brain MRI characteristics and GMFCS level at a young age can each help identify children with CP at risk for impaired cognition at school age and together have a strong predictive value.

Keywords: Cerebral palsy; Cognitive function; Cognitive impairment; MRI; Neuroimaging.