Cognitive flexibility assessment in youth with Down syndrome: Reliability, practice effects, and validity

Cognitive flexibility refers to the ability to switch between different mental sets, tasks, or strategies and is challenging for some individuals with Down syndrome (DS). The lack of reliable and valid cognitive flexibility measures for individuals with DS is a major barrier to clinical trials and intervention studies designed to address cognitive challenges specific to DS. To avoid measurement limitations that could confound interpretations of performance in clinical trials in children with DS, it is critical to use phenotype-sensitive and psychometrically sound measures of cognitive flexibility. This study aimed to evaluate the psychometric properties of three measures of cognitive flexibility including Rule-Shift, Weigl Sorting, and KiTAP Flexibility in a sample of 97 youth with DS aged 6–17 years old. Data were collected at two time points with a two-week interval. Parents also completed adaptive behavior and cognitive flexibility questionnaires. Child cognitive and language abilities were also assessed. The Weigl Sorting met the most psychometric criteria, with adequate feasibility (≥ 80 %) and significant correlations with most of the broader developmental domains; however, the levels of test-retest reliability, practice effects, and convergent validity did not meet a priori criteria. Rule-Shift and KiTAP Flexibility measures did not have acceptable feasibility; although sensitivity and specificity analyses revealed that Rule-Shift may be appropriate for a subgroup of the participants. No evaluated measures met all psychometric study criteria and, therefore, additional evaluation of cognitive flexibility measures is needed for use among individuals with DS.