Ten-year follow-up study found that motor-free intelligence quotient declined in children with mild-to-moderate cerebral palsy

Aim: This 10-year follow-up study examined cognitive change in a cohort of children with cerebral palsy from preschool to adolescence at the group and individual levels. Methods: The Wechsler Preschool and Primary Scale of Intelligence was administered to 80 children with cerebral palsy (mean = 4 years 6 months, standard deviation = 7 months) at baseline (Time 1). At 10-year follow-up (Time 2), 28 adolescents (mean = 14 years 6 months, standard deviation = 9 months) returned for assessment with the Wechsler Intelligence Scale for Children. Motor-free intelligence quotient (IQ) scores were calculated and paired-samples t-tests and the Reliable Change Index (RCI) were used to investigate change in IQ over time. Results: At the group level, nonverbal IQ scores declined significantly. At the individual level, RCI indicated nine and 11 children showed a clinically significant decline in Full Scale IQ (FSIQ) and nonverbal IQ scores, respectively. Decline in FSIQ was related to a history of seizures whereas decline in nonverbal IQ was associated with higher initial IQ. Conclusion: Cognitive abilities in children with cerebral palsy evolve over time and selective deficits may not be observable until a later age, highlighting the importance of repeated cognitive assessment throughout childhood and adolescence.