Long-Term Neuropsychological Profiles and Their Role as Mediators of Adaptive Functioning after Traumatic Brain Injury in Early Childhood

Abstract

The objectives of the study were to characterize long-term neuropsychological outcomes following traumatic brain injury (TBI) sustained during early childhood, and determine whether identified neuropsychological impairments mediated the effect of TBI on long-term adaptive functioning. Participants included 16 children with severe TBI, 42 children with moderate TBI, and 72 children with orthopedic injuries (OI) sustained between ages 3 and 7 years. Children completed neuropsychological tests and caregivers completed a structured interview of child adaptive functioning at 6.9 (±1.10) years post-injury. Profile analysis and multiple mediator modeling were employed. Children with severe TBI demonstrated poorer fluid reasoning and inhibitory control than both children with moderate TBI and OI, as well as slower processing speed than the OI group. Both fluid reasoning and processing speed were significant independent mediators of the effect of severe TBI on adaptive functioning. No neuropsychological measure significantly mediated the effect of moderate TBI on adaptive functioning. Children sustaining early severe TBI demonstrate persisting neuropsychological impairments into adolescence and young adulthood. The impact of severe TBI on children's long-term adaptive functioning is mediated in part by its effects on fluid reasoning and processing speed.

Keywords: cognitive function; neuropsychology; outcome measures; pediatric brain injury.

FIG. 1.

Results of profile analysis. Error bars are 95% confidence intervals. WASI Vocab, Wechsler Abbreviated Scale of Intelligence, Vocabulary subtest; WASI MR, Wechsler Abbreviated Scale of Intelligence, Matrix Reasoning subtest; CASL PJ, Comprehensive Assessment of Spoken Language, Pragmatic Judgment test; TOL TC, Tower of London, Second Edition, total correct score; DKEFS VF, Delis–Kaplan Executive Function System, Verbal Fluency test; TEA-Ch CC, Test of Everyday Attention for Children, Creature Counting subtest; TEA-Ch WDW, Test of Everyday Attention for Children, Walk/Don't Walk subtest; TEA-Ch CT, Test of Everyday Attention for Children, Code Transmission subtest; WISC-IV PSI, Wechsler Intelligence Scale for Children, Fourth Edition, Processing Speed Index; VPA, Verbal Paired Associates; TBI, traumatic brain injury; OI, orthopedic injury.

FIG. 2.

Direct effect pathways of group and mediator variables. α, direct effect of group on potential mediators; b, direct effect of mediator variables on adaptive functioning; c’, direct effect of group on adaptive functioning. WASI MR, Wechsler Abbreviated Scale of Intelligence, Matrix Reasoning subtest; TEA-Ch WDW, Test of Everyday Attention for Children, Walk/Don't Walk subtest; WISC-IV PSI, Wechsler Intelligence Scale for Children, Fourth Edition, Processing Speed Index; CAFAS, Child and Adolescent Functional Assessment Scale; TBI, traumatic brain injury; OI, orthopedic injury; *p < 0.05; **p < 0.01.