Developmental Associations between Cognition and Adaptive Behavior in Intellectual and Developmental Disability.

Background: Intellectual and developmental disabilities (IDDs) are associated with both cognitive challenges and difficulties in conceptual, social, and practical areas of living (DSM-5). Individuals with IDD often present with an intellectual disability in addition to a developmental disability such as autism or Down syndrome. Those with IDD may present with deficits in intellectual functioning as well as adaptive functioning that interfere with independence and living skills. The present study sought to examine associations of longitudinal developmental change in domains of cognition (NIH Toolbox Cognition Battery, NIHTB-CB) and adaptive behavior domains (Vineland Adaptive Behavior Scales-3; VABS-3) including Socialization, Communication, and Daily Living Skills (DLS) over a two-year period. Methods: Eligible participants for this multisite longitudinal study included those who were between 6 and 26 years at Visit 1, and who had a diagnosis of, or suspected intellectual disability (ID), including borderline ID. Three groups were recruited, including those with fragile X syndrome, Down syndrome, and other/idiopathic intellectual disability. In order to examine the association of developmental change between cognitive and adaptive behavior domains, bivariate latent change score (BLCS) models were fit to compare change in the three cognitive domains measured by the NIHTB-CB (Fluid, Crystallized, Composite) and the three adaptive behavior domains measured by the VABS-3 (Communication, DLS, and Socialization). Results: Over a two-year period, change in cognition (both Crystalized and Composite) was significantly and positively associated with change in daily living skills. Also, baseline cognition level predicted growth in adaptive behavior, however baseline adaptive behavior did not predict growth in cognition in any model. Conclusions: The present study demonstrated that developmental improvements in cognition and adaptive behavior are associated in children and young adults with IDD, indicating the potential for cross-domain effects of intervention. Notably, improvements in Daily Living Skills on the VABS-3 emerged as a primary area of adaptive behavior that positively related to improvements in cognition. This work provides evidence for the clinical, "real life" meaningfulness of the NIHTB-CB in IDD, and important empirical support for the NIHTB-CB as a fit-for-purpose performance-based outcome measure for this population.

Deviation scores: An innovative approach to interpreting cognitive test results for individuals with intellectual disabilities.

BACKGROUND: Students with Intellectual Disability undergo frequent cognitive testing. Testing with this population is limited by insensitivity to relative strengths and weaknesses due to floor effects. AIM: The study explored the utility of deviation scores via four case studies as a supplement to educational decision-making. METHODS: Four students with Intellectual Disability completed cognitive testing. Deviation scores were calculated using age dependent raw z-score transformations to determine deviation from the standardization sample norms. RESULTS: The application of deviation scores highlighted true relative strengths and weaknesses for students with Intellectual Disability rather than documenting previously known deficits. The four cases studies illustrated where deviation scores could, or could not, add value above and beyond traditional scoring. DISCUSSION: Deviation scores can supplement placement and service decisions for students. Practical and psychometric considerations are reviewed. CONCLUSION: The findings highlight the usefulness of deviation scores in providing meaningful information to school- and clinic-based practitioners.

The comparison of expressed emotion of parents of individuals with fragile X syndrome to other intellectual disabilities.

BACKGROUND: Parenting children and young adults with intellectual disabilities, including individuals with fragile X syndrome and Down syndrome, is challenging, joyful, and complicated. Exploring how parents talk about their children, and the quality of the parent/child relationship can provide insight into the home environment and interactional patterns of the family. METHOD: Expressed emotion (EE) is a measurement of a family's emotional climate based on a parent or caregiver's report of warmth, emotional overinvolvement, hostility, and criticism. The purpose of this study was to describe EE for a sample of parents of individuals with intellectual disabilities and to determine any differences in EE amongst individuals within subgroups. Based on previous research about fragile X syndrome and family systems, we hypothesized that there would be significant differences between the disability groups (higher EE in families with children/young adults with fragile X syndrome). RESULTS: Results showed relatively high proportions of EE across groups of individuals with intellectual disabilities, however, there were no significant differences between the subgroups. Null findings suggest that differences in EE may not relate directly to a child's specific genetic condition. Rather, increased EE in caregiver populations may simply reflect well-documented stressors related to stigma, caregiver burden, and limited community supports. Critical statements were infrequent, however, over half of the participants reported dissatisfaction with their situation, and many were categorized as having emotional overinvolvement, as measured by frequent statements of intense worry and self-sacrifice. CONCLUSION: Findings point to potential utility in family-level interventions focused on providing structured caregiver therapy to manage excessive worry and grief related to a diagnosis of intellectual disability, and respite care to encourage caregiver independence and pursuit of personal care.

Sensitivity of the NIH Toolbox to Detect Cognitive Change in Individuals With Intellectual and Developmental Disability.

BACKGROUND AND OBJECTIVE: Individuals with intellectual disability (ID) experience protracted cognitive development compared with typical youth. Sensitive measurement of cognitive change in this population is a critical need for clinical trials and other intervention studies, but well-validated outcome measures are scarce. This study's aim was to evaluate the sensitivity of the NIH Toolbox Cognition Battery (NIHTB-CB) to detect developmental changes in groups with ID-fragile X syndrome (FXS), Down syndrome (DS), and other ID (OID)-and to provide further support for its use as an outcome measure for treatment trials. METHODS: We administered the NIHTB-CB and a reference standard cross-validation measure (Stanford-Binet Intelligence Scales, Fifth Edition [SB5]) to 256 individuals with FXS, DS, and OID (ages 6-27 years). After 2 years of development, we retested 197 individuals. Group developmental changes in each cognitive domain of the NIHTB-CB and SB5 were assessed using latent change score models, and 2-year growth was evaluated at 3 age points (10, 16, and 22 years). RESULTS: Overall, effect sizes of growth measured by the NIHTB-CB tests were comparable with or exceeded those of the SB5. The NIHTB-CB showed significant gains in almost all domains in OID at younger ages (10 years), with continued gains at 16 years and stability in early adulthood (22 years). The FXS group showed delayed gains in attention and inhibitory control compared with OID. The DS group had delayed gains in receptive vocabulary compared with OID. Unlike the other groups, DS had significant growth in early adulthood in 2 domains (working memory and attention/inhibitory control). Notably, each group's pattern of NIHTB-CB growth across development corresponded to their respective pattern of SB5 growth. DISCUSSION: The NIHTB-CB is sensitive to developmental changes in individuals with ID. Comparison with levels and timing of growth on the cross-validation measure shows that the NIHTB-CB has potential to identify meaningful trajectories across cognitive domains and ID etiologies. Sensitivity to change within the context of treatment studies and delineation of clinically meaningful changes in NIHTB-CB scores, linked to daily functioning, must be established in future research to evaluate the battery more completely as a key outcome measure.

Assessing processing speed among individuals with intellectual and developmental disabilities: A match-to-sample paradigm.

Speeded Matching (SpM) is a new processing speed match-to-sample test within the NIH Toolbox Cognitive Battery. It was designed to developmentally extend feasibility to younger children or individuals with intellectual or developmental disabilities (IDD). SpM reduces cognitive demands to tapping an identical match as opposed to judging and indicating whether two stimuli are identical. In this study, we piloted SpM among 148 participants with fragile X syndrome, Down syndrome, or other intellectual disabilities (chronological age mean = 17.8 years, sd = 5.4; nonverbal mental age mean = 65 months, sd = 19.4). SpM had a high feasibility (96%) and internal consistency (rxx = 0.98). It converged well with other measures of processing speed, fluid cognition, and nonverbal mental age and diverged appropriately from crystallized cognitive skills. The correlation between nonverbal mental age and SpM in the IDD sample was not significantly different than the correlation between chronological age and SpM in a separate sample of 118 neurotypical children (age mean = 3.9 years sd = 0.8). This study provides initial evidence for the reliability and validity of the new SpM task, which may be appropriate as an outcome measure of processing speed for future clinical trials. It is more feasible than tasks designed for adults; it is brief, easy to administer, and engaging for young children and older individuals with lower mental ages associated with IDD.

Thriving with Down syndrome: A qualitative multiple case study.

BACKGROUND: Down syndrome (DS) is the most common genetic cause of intellectual disability. Prior research has primarily focused on associated medical problems and skill deficits. This study takes a novel positive psychology approach by examining critical individual characteristics and environmental factors that facilitate exceptional quality of life for people with DS. METHOD: A qualitative multiple case study design was used to document the lives of four adults thriving with DS. Thriving was defined as high subjective well-being coupled with continued personal development. RESULTS: Descriptive contexts were provided for each case along with four overarching themes: a supportive social ecology, high expectations for independence, advocacy, and strengths facilitating happiness. A new conceptual framework for understanding thriving with DS was proposed. CONCLUSIONS: These findings provide insight as to what is possible for people with DS, including ideas for future research and practice to promote thriving in the DS population.

Validation of the NIH Toolbox Cognitive Battery in intellectual disability.

OBJECTIVE: To advance the science of cognitive outcome measurement for individuals with intellectual disability (ID), we established administration guidelines and evaluated the psychometric properties of the NIH-Toolbox Cognitive Battery (NIHTB-CB) for use in clinical research. METHODS: We assessed feasibility, test-retest reliability, and convergent validity of the NIHTB-CB (measuring executive function, processing speed, memory, and language) by assessing 242 individuals with fragile X syndrome (FXS), Down syndrome (DS), and other ID, ages 6 through 25 years, with retesting completed after 1 month. To facilitate accessibility and measurement accuracy, we developed accommodations and standard assessment guidelines, documented in an e-manual. Finally, we assessed the sensitivity of the battery to expected syndrome-specific cognitive phenotypes. RESULTS: Above a mental age of 5.0 years, all tests had excellent feasibility. More varied feasibility across tests was seen between mental ages of 3 and 4 years. Reliability and convergent validity ranged from moderate to strong. Each test and the Crystallized and Fluid Composite scores correlated moderately to strongly with IQ, and the Crystallized Composite had modest correlations with adaptive behavior. The NIHTB-CB showed known-groups validity by detecting expected executive function deficits in FXS and a receptive language deficit in DS. CONCLUSION: The NIHTB-CB is a reliable and valid test battery for children and young adults with ID with a mental age of ≈5 years and above. Adaptations for very low-functioning or younger children with ID are needed for some subtests to expand the developmental range of the battery. Studies examining sensitivity to developmental and treatment changes are now warranted.

The expressed emotion of parents of children with developmental disabilities: A meta-analysis.

Parents of children with Developmental Disabilities (DD) face particular challenges interacting with their children and have been shown to have higher levels of stress than parents of children without disabilities. A number of studies have attempted to understand the emotional climate in the homes of children with DD by examining parental Expressed Emotion (EE), or parental attitudes about the child and their relationship. However, many of these studies have been small in sample size and have only worked with one subset of the DD population. This meta-analysis examined the proportion of parents of children with DD exhibiting High EE through a statistical aggregation of effect sizes across seven studies including 600 participants. The fixed effects size proportion was .39 (SE = .02; p < .0001), indicating approximately 40% of the parents in the combined samples exhibited High EE. Results support efforts to address the needs of the whole family for children with DD in order to ensure a safe and supportive emotional climate in the home.

The NIH Toolbox Cognitive Battery for intellectual disabilities: three preliminary studies and future directions.

BACKGROUND: Recent advances in understanding molecular and synaptic mechanisms of intellectual disabilities (ID) in fragile X syndrome (FXS) and Down syndrome (DS) through animal models have led to targeted controlled trials with pharmacological agents designed to normalize these underlying mechanisms and improve clinical outcomes. However, several human clinical trials have failed to demonstrate efficacy of these targeted treatments to improve surrogate behavioral endpoints. Because the ultimate index of disease modification in these disorders is amelioration of ID, the validation of cognitive measures for tracking treatment response is essential. Here, we present preliminary research to validate the National Institutes of Health Toolbox Cognitive Battery (NIH-TCB) for ID. METHODS: We completed three pilot studies of patients with FXS (total n = 63; mean age 19.3 ± 8.3 years, mean mental age 5.3 ± 1.6 years), DS (n = 47; mean age 16.1 ± 6.2, mean mental age 5.4 ± 2.0), and idiopathic ID (IID; n = 16; mean age 16.1 ± 5.0, mean mental age 6.6 ± 2.3) measuring processing speed, executive function, episodic memory, word/letter reading, receptive vocabulary, and working memory using the web-based NIH-TB-CB, addressing feasibility, test-retest reliability, construct validity, ecological validity, and syndrome differences and profiles. RESULTS: Feasibility was good to excellent (≥80 % of participants with valid scores) for above mental age 4 years for all tests except list sorting (working memory). Test-retest stability was good to excellent, and convergent validity was similar to or better than results obtained from typically developing children in the normal sample for executive function and language measures. Examination of ecological validity revealed moderate to very strong correlations between the NIH-TCB composite and adaptive behavior and full-scale IQ measures. Syndrome/group comparisons demonstrated significant deficits for the FXS and DS groups relative to IID on attention and inhibitory control, a significant reading weakness for FXS, and a receptive vocabulary weakness for DS. CONCLUSIONS: The NIH-TCB has potential for assessing important dimensions of cognition in persons with ID, and several tests may be useful for tracking response to intervention. However, more extensive psychometric studies, evaluation of the NIH-TCB's sensitivity to change, both developmentally and in the context of treatment, and perhaps establishing links to brain function in these populations, are required to determine the true utility of the battery as a set of outcome measures.