Executive Functions in a Population of Individuals with CHARGE Syndrome: Findings from Performance-Based and Rating Scale Measures According to a 3-Factor Model.

PURPOSE: To identify possible predictors of executive functions of individuals with CHARGE syndrome, as these will be important targets for interventions. METHODS: A population-based cross-sectional study investigating the executive functions of a representative sample of 35 Norwegians with CHARGE syndrome divided into two subgroups to handle their inherent heterogeneity. Both performance-based measures and rating scale findings were included and organized according to the 3-factor model of Miyake and colleagues. RESULTS: Both measures showed comprehensive executive dysfunctions within the population, which were largely unrelated to deafblindness. Working memory stood out as a strength within the executive domain and the only factor presenting results within the normal range. Verbal working memory was a particular cognitive resource for participants with deafblindness, and, unlike those without deafblindness, unrelated to sensorimotor functions. CONCLUSIONS: Individuals with CHARGE syndrome appear to be at risk for underdeveloped executive functions due to neurogenetic and environmental factors. Performance-based measures and ratings from caregivers gave unique and complementary knowledge and implied the need of both when investigating executive functioning in CHARGE syndrome. Participants with deafblindness presented strong verbal working memory despite their auditory impairments, indicating effective compensatory mechanisms The results also indicated an untapped cognitive potential in both subgroups. Because of their relatively advanced working memory significantly correlating with global cognition, the environment should assume equal learning potential of individuals with CHARGE syndrome regardless of their degree of sensory impairments.

The assessment and diagnosis of intellectual disability when development is atypical. A Norwegian population study of individuals with CHARGE syndrome.

AIM: This paper aimed to answer how psychometric methods based on neurotypical populations can serve as valid instruments in the assessment and diagnosis of intellectual disability in individuals with atypical development. The genetic, structural, and functional features of CHARGE make it uniquely suited to address this question. METHOD: A Norwegian population of individuals with CHARGE (N = 35) underwent assessment procedures according to DSM-5 guidelines for the evaluation of an intellectual disability diagnosis. Results from cognitive testing (Wechsler Intelligence Scales) and parental evaluation of adaptive skills (Vineland Adaptive Behavioral Scale) were obtained and compared to their respective norm samples to explore any methodological inconsistencies. RESULT: Significant differences emerged between the participants and the norm samples. Global cognition obtained from Wechsler revealed a bimodal distribution, suggesting a two-group sample, with the youngest children forming their own subgroup. Comparisons of the different age-groups' performances demonstrated the lowest results among the preschoolers while the adults scored the highest. The global adaptive behavior score turned out significantly lower than the performance-based scores, thereby deflating the overall estimate of global intellectual abilities. CONCLUSION: For individuals with CHARGE, the effect of the atypicality seemed most apparent during early childhood, stabilizing and subsiding towards adulthood. The test results' interpretability was weakest for the preschoolers progressively increasing until peaking in adulthood, emphasizing the importance of delaying the assessment and diagnosis of intellectual disability. Because of several validity issues connected to the observation-based measure, complementary testing should precede clinical evaluations when possible in the diagnostics of individuals with CHARGE.