Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Children with positional plagiocephaly and/or brachycephaly (PPB) had significantly lower scores in global cognitive ability (GCA), nonverbal reasoning, verbal, and working memory scores compared to unaffected controls undergoing neuropsychological assessment.

2. Children with PPB also had lower achievement scores for math, reading and writing, but these differences were not significant.

Evidence Rating: Level 1 (Excellent)

Study Rundown:

Children with PPB have demonstrated mild developmental delays during infancy and toddlerhood compared to unaffected children. Less is known about how these differences evolve during school-age years. In this prospective cohort study, researchers at Seattle Children’s Craniofacial Center aimed to evaluate differences in cognition (Differential Ability Scales, Second Edition [DAS-2 scores]) and academic achievement (Wechsler Individual Achievement Test, Third Edition [WIAT-3 scores]) in school-age children with PBB compared to controls. In adjusted analyses for sex, race, age and socioeconomic status (SES), children with PPB generally had significantly lower mean scores for DAS-2, including GCA, nonverbal reasoning, verbal, and working memory scores. In adjusted analyses for WIAT-3 scores, children with PBB had lower mathematics, total reading, and written expression scores compared to controls, but these differences were not significant. The mean adjusted DAS-2 and WIAT-3 scores for both groups still fell within the average range relative to test norms, which the authors acknowledge might be secondary to having at baseline, a low risk biological and social sample. Additionally, in analyses stratifying PPB by severity, case-control differences were consistently larger for moderate to severe PPB compared to mild PPB children. Limitations of the study included differential attrition and bias introduced from recruitment from a subspecialty clinic and participant registry. Pending future prospective data that is more population-based, the authors suggest that for pediatricians, PPB may serve as an early marker for developmental vulnerability (i.e. neuromotor deficits limiting physical repositioning), warranting higher developmental vigilance for children with PPB.

In-Depth [prospective cohort]:

A total of 149 out of 237 controls and 187 out of 235 children with PPB were included in the final analysis, and 8 children out of both the control and PPB group were unable to participate in the school-age assessment. Two pediatricians scored skull deformity on a 3-point system using 3D surface images and had excellent (κ = 0.80) and good (κ = 0.72) interrater agreement for distinguishing between the presence versus absence of skull deformity and severity of skull deformity, respectively. Children born premature (<35 weeks’ gestational age), with neurodevelopmental conditions and sensory impairments were excluded. Both groups were predominantly male (PPB = 66%, control = 57%), white and non-Hispanic (PPB = 69%, control = 60%) and high socioeconomic status. The mean age of follow-up in the PPB and controls groups was 9 ± 0.8 years and 8.8 years ± 0.6 respectively. Primary outcomes included DAS-2 and WIAT-3 scores. In adjusted analyses for DAS-2 scores, the PPB group had significantly lower GCA (mean difference effect size [ES] = – 4.26, p = 0.002), nonverbal reasoning, (ES = 0 4.00, p <0.01), verbal (ES = -4.66, p = 0.001) and working memory (ES = -3.33, p = 0.01) scores. There were no significant differences for DAS-2 processing speed and spatial scores between the 2 groups. In adjusted analyses for WIAT-3 scores, the PPB group had lower mathematics, total reading, and written expression scores, but these findings were not statistically significant. Despite these differences, the mean DAS-2 and WIAT scores for both groups were still within normal test reference ranges. Finally, analyses stratifying the severity of PBB showed that mean differences relative to controls were greater in children with moderate to severe PPB versus mild PPB.

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