Integrating Data Across Multiple Sites in the Northeastern United States to Examine Associations Between a Prenatal Metal Mixture and Child Cognition.

We applied a novel hierarchical Bayesian weighted quantile sum (HBWQS) regression to combine data across 3 study sites to examine associations between prenatal exposure to metals and cognitive functioning in childhood. Data from 326 mother-child dyads enrolled in an ongoing cohort study, the Programming of Intergenerational Stress Mechanisms (PRISM) Study, based in New York, New York (recruitment in 2013-2020) and Boston, Massachusetts (recruitment 2011-2013), and the First Thousand Days of Life (FTDL) cohort study (recruitment 2012-2019), based in northern Virginia, were used. Arsenic, cadmium, manganese, lead, and antimony were measured in urine collected during pregnancy. Cognitive functioning was assessed in children aged 3-11 years using the National Institutes of Health Toolbox Cognition Battery. The HBWQS regression showed a negative association between the urinary metal mixture and the Cognition Early Childhood Composite Score in the PRISM New York City (ß = -3.67, 95% credible interval (CrI): -7.61, -0.01) and FTDL (ß = -3.76, 95% CrI: -7.66, -0.24) samples, with a similar trend in the PRISM Boston sample (ß = -3.24, 95% CrI: -6.77, 0.144). We did not detect these associations in traditionally pooled models. HBWQS regression allowed us to account for site heterogeneity and detect associations between prenatal metal-mixture exposure and cognitive outcomes in childhood. Given the ubiquity of metals exposure, interventions aimed at reducing prenatal exposure may improve cognitive outcomes in children. This article is part of a Special Collection on Environmental Epidemiology.

Life satisfaction for adolescents with developmental and behavioral disabilities during the COVID-19 pandemic.

BACKGROUND: This study aimed to identify contextual factors associated with life satisfaction during the COVID-19 pandemic for adolescents with mental, emotional, behavioral, and developmental (MEBD) disabilities. METHODS: Data were collected from a sample of 1084 adolescents aged 11-21 years from April 2020 to August 2021. This cross-sectional study used a sequential machine learning workflow, consisting of random forest regression and evolutionary tree regression, to identify subgroups of adolescents in the Environmental influences on Child Health Outcomes (ECHO) consortium who demonstrated enhanced vulnerability to lower life satisfaction as described by intersecting risk factors, protective factors, and MEBD disabilities. RESULTS: Adolescents with a history of depression, anxiety, autism, and attention-deficit/hyperactivity disorder were particularly susceptible to decreased life satisfaction in response to unique combinations of stressors experienced during the COVID-19 pandemic. These stressors included decreased social connectedness, decreased family engagement, stress related to medical care access, pandemic-related traumatic stress, and single-caregiver households. CONCLUSION: Findings from this study highlight the importance of interventions aimed specifically at increasing adolescent social connectedness, family engagement, and access to medical support for adolescents with MEBD disabilities, particularly in the face of stressors, such as a global pandemic. IMPACT: Through a machine learning process, we identified contextualized risks associated with life satisfaction among adolescents with neurodevelopmental disabilities during the COVID-19 pandemic. The COVID-19 pandemic resulted in large-scale social disruptions for children and families. Such disruptions were associated with worse mental health outcomes in the general pediatric population, but few studies have examined specific subgroups who may be at heightened risk. We endeavored to close that gap in knowledge. This study highlights the importance of social connectedness, family engagement, and access to medical support as contributing factors to life satisfaction during the COVID-19 pandemic for adolescents with neurodevelopmental disabilities.

Exploring symptom clusters in mild cognitive impairment and dementia with the NIH Toolbox.

OBJECTIVE: Symptom clustering research provides a unique opportunity for understanding complex medical conditions. The objective of this study was to apply a variable-centered analytic approach to understand how symptoms may cluster together, within and across domains of functioning in mild cognitive impairment (MCI) and dementia, to better understand these conditions and potential etiological, prevention, and intervention considerations. METHOD: Cognitive, motor, sensory, emotional, and social measures from the NIH Toolbox were analyzed using exploratory factor analysis (EFA) from a dataset of 165 individuals with a research diagnosis of either amnestic MCI or dementia of the Alzheimer's type. RESULTS: The six-factor EFA solution described here primarily replicated the intended structure of the NIH Toolbox with a few deviations, notably sensory and motor scores loading onto factors with measures of cognition, emotional, and social health. These findings suggest the presence of cross-domain symptom clusters in these populations. In particular, negative affect, stress, loneliness, and pain formed one unique symptom cluster that bridged the NIH Toolbox domains of physical, social, and emotional health. Olfaction and dexterity formed a second unique cluster with measures of executive functioning, working memory, episodic memory, and processing speed. A third novel cluster was detected for mobility, strength, and vision, which was considered to reflect a physical functioning factor. Somewhat unexpectedly, the hearing test included did not load strongly onto any factor. CONCLUSION: This research presents a preliminary effort to detect symptom clusters in amnestic MCI and dementia using an existing dataset of outcome measures from the NIH Toolbox.

Mobile toolbox (MTB) remote measures of executive function and processing speed: development and validation.

OBJECTIVE: The ability to remotely monitor cognitive skills is increasing with the ubiquity of smartphones. The Mobile Toolbox (MTB) is a new measurement system that includes measures assessing Executive Functioning (EF) and Processing Speed (PS): Arrow Matching, Shape-Color Sorting, and Number-Symbol Match. The purpose of this study was to assess their psychometric properties. METHOD: MTB measures were developed for smartphone administration based on constructs measured in the NIH Toolbox® (NIHTB). Psychometric properties of the resulting measures were evaluated in three studies with participants ages 18 to 90. In Study 1 (N = 92), participants completed MTB measures in the lab and were administered both equivalent NIH TB measures and other external measures of similar cognitive constructs. In Study 2 (N = 1,021), participants completed the equivalent NIHTB measures in the lab and then took the MTB measures on their own, remotely. In Study 3 (N = 168), participants completed MTB measures twice remotely, two weeks apart. RESULTS: All three measures exhibited very high internal consistency and strong test-retest reliability, as well as moderately high correlations with comparable NIHTB tests and moderate correlations with external measures of similar constructs. Phone operating system (iOS vs. Android) had a significant impact on performance for Arrow Matching and Shape-Color Sorting, but no impact on either validity or reliability. CONCLUSIONS: Results support the reliability and convergent validity of MTB EF and PS measures for use across the adult lifespan in remote, self-administered designs.

The NIH Infant and Toddler Toolbox: A new standardized tool for assessing neurodevelopment in children ages 1-42 months.

The progress of developmental research demands reliable measurement techniques, yet inconsistency persist across laboratories, subfields, and settings. To address this, the NIH Toolbox for Neurological and Behavioral Function (NIHTB)® has been extended to create a universal assessment for developmental and pediatric communities: The NIH Infant and Toddler ("Baby") Toolbox. Currently undergoing norming in a sample of 2550 children demographically representative of the 2020 U.S. census, the Baby Toolbox is slated for release in late 2024. This paper introduces the Baby Toolbox, details its objectives, development, and technological innovations, describes plans for reliability and norming, and invites researchers to consider the Baby Toolbox in the future studies. Ultimately, this initiative stands to enhance cross-study comparability and advance comprehensive developmental evaluation.

Using the Mobile Toolbox in child and adolescent samples: A feasibility study.

Cognitive research with developmental samples requires improved methods that support large-scale, diverse, and open science. This paper offers initial evidence to support the Mobile Toolbox (MTB), a self-administered remote smartphone-based cognitive battery, in youth populations, from a pilot sample of 99 children (Mage = 11.79 years; 36% female; 53% White, 33% Black or African American, 9% Asian, and 15% Hispanic). Completion rates (95%-99%), practice performance (96%-100%), internal consistency (0.60-0.98), and correlations with similar NIHTB measures (0.55-0.77) provide the first evidence to support the MTB in a youth sample, although there were some inconsistencies across measures. Preliminary findings provide promising evidence of the MTB in developmental populations, and further studies are encouraged.

Evaluation of the NIH Toolbox Odor Identification Test across normal cognition, amnestic mild cognitive impairment, and dementia due to Alzheimer's disease.

INTRODUCTION: Olfactory decline is associated with cognitive decline in aging, amnestic mild cognitive impairment (aMCI), and amnestic dementia associated with Alzheimer's disease neuropathology (ADd). The National Institutes of Health Toolbox Odor Identification Test (NIHTB-OIT) may distinguish between these clinical categories. METHODS: We compared NIHTB-OIT scores across normal cognition (NC), aMCI, and ADd participants (N = 389, ≥65 years) and between participants positive versus negative for AD biomarkers and the APOE ε4 allele. RESULTS: NIHTB-OIT scores decreased with age (p < 0.001) and were lower for aMCI (p < 0.001) and ADd (p < 0.001) compared to NC participants, correcting for age and sex. The NIHTB-OIT detects aMCI (ADd) versus NC participants with 49.4% (56.5%) sensitivity and 88.8% (89.5%) specificity. NIHTB-OIT scores were lower for participants with positive AD biomarkers (p < 0.005), but did not differ based on the APOE ε4 allele (p > 0.05). DISCUSSION: The NIHTB-OIT distinguishes clinically aMCI and ADd participants from NC participants. HIGHLIGHTS: National Institutes of Health Toolbox Odor Identification Test (NIHTB-OIT) discriminated normal controls from mild cognitive impairment. NIHTB-OIT discriminated normal controls from Alzheimer's disease dementia. Rate of olfactory decline with age was similar across all diagnostic categories. NIHTB-OIT scores were lower in participants with positive Alzheimer's biomarker tests. NIHTB-OIT scores did not differ based on APOE genotype.

Baseline characterization of the ARMADA (Assessing Reliable Measurement in Alzheimer's Disease) study cohorts.

INTRODUCTION: The National Institutes of Health (NIH) Toolbox (NIHTB) provides computerized measures of cognition, emotion, sensation, and motor abilities across the lifespan. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study validated the NIHTB in individuals across the cognitive aging spectrum. This article reports the characteristics of our sample of participants. METHODS: Participants were recruited across nine sites and classified clinically as cognitively normal (NC), with mild cognitive impairment (MCI), or with dementia of the Alzheimer's type (DAT.) They completed the NIHTB at multiple time points and many had at least one Alzheimer's biomarker previously obtained. RESULTS: Groups differed with respect to dementia severity levels, as anticipated, but were well-matched across many demographic characteristics. DISCUSSION: The ARMADA study demographics and baseline characteristics provide a suitable sample for validating the NIHTB across the cognitive aging spectrum. Other enriched samples (African American participants, Spanish NIHTB, 85+ years of age) will be reported elsewhere. HIGHLIGHTS: There is a need for assessments that can detect the early stages of cognitive decline in older adults. The ARMADA (Assessing Reliable Measurement in Alzheimer's Disease and Cognitive Aging) study will validate the National Institutes of Health (NIH) Toolbox across the aging spectrum, including mild cognitive impairment (MCI) and dementia of the Alzheimer's type (DAT). Here we report the characteristics of participants. Groups were well-matched across most demographic characteristics, and clinical characteristics differed as expected. ARMADA study cohorts reflect their respective clinical syndromes for validating the NIH Toolbox.

Validation of a tablet-based assessment of auditory sensitivity for researchers.

Quantifying hearing acuity is increasingly important across a wide range of research areas in the behavioral and neurosciences. Scientists have relied on either self-reported hearing status or the availability of diagnostic hearing assessment in past studies. There remains a need for a valid and reliable assessment of auditory sensitivity that can provide estimates of the magnitude of hearing loss, if present, without requirements for professional audiologists, facilities, and equipment that are needed to conduct a diagnostic hearing assessment. The goal of this experiment was to validate the NIH Toolbox® Hearing Threshold Test (HTT), a tablet-based hearing assessment available via iPad application that uses consumer-grade headphones, on a clinical sample of children and adults with varying degrees of hearing acuity. Electroacoustic analysis of the hearing assessment application and headphones demonstrated acoustic outputs within established conformity standards for hearing assessment. Twenty-seven children and 63 adults participated in a standard diagnostic hearing assessment and the experimental tablet-based assessment. The results showed that thresholds from the tablet-based assessment were highly correlated with thresholds from the clinical hearing assessment (r = .83-.93) for children and adults for all frequencies and across a range of levels of hearing acuity. The HTT also met clinical test-retest reliability standards (Cronbach's α > .86). The tablet-based hearing assessment provides acceptable estimates of hearing levels for children and adults when diagnostic audiometric assessment capabilities are not available.

Prenatal exposure to PM2.5 and childhood cognition: Accounting for between-site heterogeneity in a pooled analysis of ECHO cohorts in the Northeastern United States.

BACKGROUND: Emerging studies have investigated the adverse health effects of PM2.5 using data from multiple cohorts, and results often are not generalizable across cohorts. We aimed to assess associations between prenatal PM2.5 and childhood cognition in two U.S. cohorts while accounting for between-site heterogeneity. METHODS: Analyses included 348 mother-child dyads enrolled in the dual site (New York City and Boston) PRogramming of Intergenerational Stress Mechanisms (PRISM) cohort and in the First Thousand Days of Life (FTDL) study (Northern Virginia) participating in the Environmental influences on Child Health Outcomes (ECHO) national consortium. Residential prenatal PM2.5 exposure was estimated using a validated satellite-based model and childhood cognition was measured using the NIH Toolbox Cognition Battery at three to eight years of age. We used a log-linear model applied to contingency tables formed by cross-classifying covariates by site to examine between-site heterogeneity using 3rd trimester PM2.5 exposure, age-corrected cognition scores, and covariates potentially causing heterogeneities. Multivariable linear regression models informed by the combinability analysis were used to estimate the coefficients and 95% confidence intervals (CIs) for the association between 3rd trimester PM2.5 exposure and age-corrected cognition scores (mean = 100, SD = 15). RESULTS: The log-linear model indicated that inter-study associations were similar between PRISM-NYC and FTDL, which were different from those in PRISM-Boston. Accordingly, we combined the data of PRISM-NYC and FTDL cohorts. We observed associations between 3rd trimester PM2.5 and cognition scores, findings were varying by site, childsex, and test. For example, a 1 µg/m3 increase of 3rd trimester PM2.5 was associated with -4.35 (95% CI = -8.73, -0.25) mean early childhood cognition scores in females in PRISM-Boston. In the pooled NYC + FTDL site, the association between PM2.5 and childhood cognition may be modified by maternal education and urbanicity. CONCLUSIONS: We found associations between prenatal PM2.5 and impaired childhood cognition. Since multi-site analyses are increasingly conducted, our findings suggest the needed awareness of between-site heterogeneity.

New complementary perspectives for inpatient physical function assessment: matched clinician-report and patient-report short form measures from the PROMIS adult physical function item bank.

PURPOSE: To develop two item content-matched, precise, score-level targeted inpatient physical function (PF) short form (SF) measures: one clinician-reported, one patient-reported. Items were derived from PROMIS PF bank content; scores are reported on the PROMIS PF T-score metric. METHODS: The PROMIS PF item bank was reviewed for content measuring lower-level PF status (T-scores 10-50) with high item set score-level reliability (≥ 0.90). Selected patient-reported (PR) items were also edited to function as clinician-reported (CR) items. Items were reviewed by clinicians and field tested; responses were assessed for meeting PROMIS measure development standards. New CR and PR items were calibrated using patient responses to the original PROMIS PF items as anchoring data. SFs were constructed, based on content and precision. RESULTS: Nine PROMIS PF items were candidates for CR and PR inpatient PF assessment; three new items were written to extend content coverage. An inpatient sample (N = 515; 55.1% female; mean age = 66.2 years) completed 12 PR items and was assessed by physical therapists (using 12 CR items). Analyses indicated item sets met expected measure development standards. Twelve new CR and three new PR items were linked to the PROMIS PF metric (raw score r = 0.73 and 0.90, respectively). A 5-item CR SF measure was constructed; score-level reliabilities were ≥ 0.90 for T-scores 13-45. A 5-item PR SF measure was assembled, mirroring CR SF content. CONCLUSIONS: Two item content-matched SFs have been developed for clinician and patient reporting and are an effective, efficient means of assessing inpatient PF and offer complementary perspectives.

Challenges in Participant Engagement and Retention Using Mobile Health Apps: Literature Review.

BACKGROUND: Mobile health (mHealth) apps are revolutionizing the way clinicians and researchers monitor and manage the health of their participants. However, many studies using mHealth apps are hampered by substantial participant dropout or attrition, which may impact the representativeness of the sample and the effectiveness of the study. Therefore, it is imperative for researchers to understand what makes participants stay with mHealth apps or studies using mHealth apps. OBJECTIVE: This study aimed to review the current peer-reviewed research literature to identify the notable factors and strategies used in adult participant engagement and retention. METHODS: We conducted a systematic search of PubMed, MEDLINE, and PsycINFO databases for mHealth studies that evaluated and assessed issues or strategies to improve the engagement and retention of adults from 2015 to 2020. We followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Notable themes were identified and narratively compared among different studies. A binomial regression model was generated to examine the factors affecting retention. RESULTS: Of the 389 identified studies, 62 (15.9%) were included in this review. Overall, most studies were partially successful in maintaining participant engagement. Factors related to particular elements of the app (eg, feedback, appropriate reminders, and in-app support from peers or coaches) and research strategies (eg, compensation and niche samples) that promote retention were identified. Factors that obstructed retention were also identified (eg, lack of support features, technical difficulties, and usefulness of the app). The regression model results showed that a participant is more likely to drop out than to be retained. CONCLUSIONS: Retaining participants is an omnipresent challenge in mHealth studies. The insights from this review can help inform future studies about the factors and strategies to improve participant retention.

ARMADA: Assessing reliable measurement in Alzheimer's disease and cognitive aging project methods.

INTRODUCTION: Early detection of cognitive decline in older adults is a public health priority. Advancing Reliable Measurement in Alzheimer's Disease and Cognitive Aging (ARMADA), a multisite study, is validating cognition, emotion, motor, and sensory modules of the National Institutes of Health Toolbox for Assessment of Neurological and Behavioral Function (NIHTB) in the aging spectrum from cognitively normal to dementia of the Alzheimer's type (DAT). METHODS: Participants 65 to 85 years old, in demographic groups racially proportional to the general US population, are recruited in one of three groups to validate the NIHTB: cognitively normal, amnestic mild cognitive impairment (aMCI), or mild DAT. Additional special emphasis cohorts include (1) Blacks in the three clinical groups; (2) Spanish-speakers in the three clinical groups; (3) cognitively normal, population-proportional, over age 85. DISCUSSION: Longitudinal study will determine whether NIHTB can predict cognitive decline and is associated with Alzheimer's disease biomarkers. Here, we detail the methods for the ARMADA study.

The NIH Toolbox: Overview of Development for Use with Hispanic Populations.

OBJECTIVE: Hispanics/Latinos are the largest and fastest-growing minority population in the United States. To facilitate appropriate outcome assessment of this expanding population, the NIH Toolbox for Assessment of Neurological and Behavioral Function® (NIH Toolbox®) was developed with particular attention paid to the cultural and linguistic needs of English- and Spanish-speaking Hispanics/Latinos. METHODS: A Cultural Working Group ensured that all included measures were appropriate for use with Hispanics/Latinos in both English and Spanish. In addition, a Spanish Language Working Group assessed all English-language NIH Toolbox measures for translatability. RESULTS: Measures were translated following the Functional Assessment of Chronic Illness Therapy (FACIT) translation methodology for instances where language interpretation could impact scores, or a modified version thereof for more simplified translations. The Spanish versions of the NIH Toolbox Cognition Battery language measures (i.e., Picture Vocabulary Test, Oral Reading Recognition Test) were developed independently of their English counterparts. CONCLUSIONS: The Spanish-language version of the NIH Toolbox provides a much-needed set of tools that can be selected as appropriate to complement existing protocols being conducted with the growing Hispanic/Latino population in the United States.

PROMIS® Adult Health Profiles: Efficient Short-Form Measures of Seven Health Domains.

BACKGROUND: There is a need for valid self-report measures of core health-related quality of life (HRQoL) domains. OBJECTIVE: To derive brief, reliable and valid health profile measures from the Patient Reported Outcomes Measurement Information System® (PROMIS®) item banks. METHODS: Literature review, investigator consensus process, item response theory (IRT) analysis, and expert review of scaling results from multiple PROMIS data sets. We developed 3 profile measures ranging in length from 29 to 57 questions. These profiles assess important HRQoL domains with highly informative subsets of items from respective item banks and yield reliable information across mild-to-severe levels of HRQoL experiences. Each instrument assesses the domains of pain interference, fatigue, depression, anxiety, sleep disturbance, physical function, and social function using 4-, 6-, and 8-item short forms for each domain, and an average pain intensity domain score, using a 0-10 numeric rating scale. RESULTS: With few exceptions, all domain short forms within the profile measures were highly reliable across at least 3 standard deviation (30 T-score) units and were strongly correlated with the full bank scores. Construct validity with ratings of general health and quality of life was demonstrated. Information to inform statistical power for clinical and general population samples is also provided. CONCLUSIONS: Although these profile measures have been used widely, with summary scoring routines published, description of their development, reliability, and initial validity has not been published until this article. Further evaluation of these measures and clinical applications are encouraged.

Measurement framework for the Environmental influences on Child Health Outcomes research program.

PURPOSE OF REVIEW: Diverse methodological approaches pose significant challenges to assess environmental exposure effects on child health outcomes. Although transdisciplinary research efforts offer unique opportunities for understanding the complex and multidimensional facets of lifespan health and disease trajectories, a shared measurement strategy is necessary for ensuring cohesion and comprehensibility across disciplines and domains. RECENT FINDINGS: Exposure science often focuses on one life stage, one primary outcome domain and/or one environmental context without regard for understanding the complexity of exposome pathways and outcomes across a developmental continuum. As part of the National Institutes of Health Environmental influences on Child Health Outcomes Program, the Person Reported Outcomes Core developed a unifying measurement framework that takes a lifespan development approach to assess physical, mental and social health outcomes within the complex matrix of environmental exposure pathways. SUMMARY: The proposed framework offers a shared methodological approach to health outcome assessment, with a particular emphasis on person-reported outcomes. This framework will be instrumental for future large-scale consortia and transdisciplinary team science efforts by providing a common structure, measurement guidance and consistent terminology.

Grooming a CAT: customizing CAT administration rules to increase response efficiency in specific research and clinical settings.

PURPOSE: To evaluate the degree to which applying alternative stopping rules would reduce response burden while maintaining score precision in the context of computer adaptive testing (CAT). DATA: Analyses were conducted on secondary data comprised of CATs administered in a clinical setting at multiple time points (baseline and up to two follow ups) to 417 study participants who had back pain (51.3%) and/or depression (47.0%). Participant mean age was 51.3 years (SD = 17.2) and ranged from 18 to 86. Participants tended to be white (84.7%), relatively well educated (77% with at least some college), female (63.9%), and married or living in a committed relationship (57.4%). The unit of analysis was individual assessment histories (i.e., CAT item response histories) from the parent study. Data were first aggregated across all individuals, domains, and time points in an omnibus dataset of assessment histories and then were disaggregated by measure for domain-specific analyses. Finally, assessment histories within a "clinically relevant range" (score ≥ 1 SD from the mean in direction of poorer health) were analyzed separately to explore score level-specific findings. METHOD: Two different sets of CAT administration rules were compared. The original CAT (CATORIG) rules required at least four and no more than 12 items be administered. If the score standard error (SE) reached a value < 3 points (T score metric) before 12 items were administered, the CAT was stopped. We simulated applying alternative stopping rules (CATALT), removing the requirement that a minimum four items be administered, and stopped a CAT if responses to the first two items were both associated with best health, if the SE was < 3, if SE change < 0.1 (T score metric), or if 12 items were administered. We then compared score fidelity and response burden, defined as number of items administered, between CATORIG and CATALT. RESULTS: CATORIG and CATALT scores varied little, especially within the clinically relevant range, and response burden was substantially lower under CATALT (e.g., 41.2% savings in omnibus dataset). CONCLUSIONS: Alternate stopping rules result in substantial reductions in response burden with minimal sacrifice in score precision.

Normative Two-Minute Walk Test Distances for Boys and Girls 3 to 17 Years of Age.

AIMS: To provide normative reference values for the 2-minute walk test (2MWT) for children and adolescents. METHODS: A population-based sample of 2,631 boys and girls (3-17 years) contributed data to this 2011 study which was part of the NIH Toolbox for the Assessment of Neurological and Behavioral Function Norming Project. The 2MWT was performed over a 50 foot (15.2 meter) out-and-back course. RESULTS: Overall, the mean (standard deviation) distance walked by the participants was 186.2 (33.9) meters. As a general linear model demonstrated that gender (F = 11.0, p =.001) and age (F = 127.6, p <.001) affected 2MWT distance, separate norms are provided for each gender and age stratum (e.g., 3-year-old boys,16-year-old girls). Based on these findings and correlational and regression analysis, separate explanatory equations for 2MWT distance for boys and girls are provided. The separate equations for boys and girls include age, age squared, height, and body mass as variables that explain around 40% of the variance in 2MWT distance. CONCLUSIONS: The study presents norms for the 2MWT performed by American boys and girls. The norms can be used to determine the presence of limitations in walking endurance in this population.

Handgrip Strength: A Population-Based Study of Norms and Age Trajectories for 3- to 17-Year-Olds.

PURPOSE: To provide normative values and equations for grip strength obtained from a population-based sample of individuals 3 to 17 years of age. METHODS: This cross-sectional study used grip strength data from 2706 participants (49.2% males, 91% right-hand dominant) in the normative phase of the National Institutes of Health Toolbox project. RESULTS: Analyses showed greater strength in the dominant hand in boys and with each yearly increase in age. Normative data are presented separately for each side, sex, and age. Separate regression equations using age and weight as explanatory variables of grip strength are provided for each side by sex. CONCLUSIONS: The normative data can serve as a guide for interpreting grip strength measurements. The trajectories can be used to investigate the effect of various pathologies and conditions on grip strength during physical maturation.

Demographically Corrected Normative Standards for the Spanish Language Version of the NIH Toolbox Cognition Battery.

Hispanics are the fastest growing ethnicity in the United States, yet there are limited well-validated neuropsychological tools in Spanish, and an even greater paucity of normative standards representing this population. The Spanish NIH Toolbox Cognition Battery (NIHTB-CB) is a novel neurocognitive screener; however, the original norms were developed combining Spanish- and English-versions of the battery. We developed normative standards for the Spanish NIHTB-CB, fully adjusting for demographic variables and based entirely on a Spanish-speaking sample. A total of 408 Spanish-speaking neurologically healthy adults (ages 18-85 years) and 496 children (ages 3-7 years) completed the NIH Toolbox norming project. We developed three types of scores: uncorrected based on the entire Spanish-speaking cohort, age-corrected, and fully demographically corrected (age, education, sex) scores for each of the seven NIHTB-CB tests and three composites (Fluid, Crystallized, Total Composites). Corrected scores were developed using polynomial regression models. Demographic factors demonstrated medium-to-large effects on uncorrected NIHTB-CB scores in a pattern that differed from that observed on the English NIHTB-CB. For example, in Spanish-speaking adults, education was more strongly associated with Fluid scores, but showed the strongest association with Crystallized scores among English-speaking adults. Demographic factors were no longer associated with fully corrected scores. The original norms were not successful in eliminating demographic effects, overestimating children's performances, and underestimating adults' performances on the Spanish NIHTB-CB. The disparate pattern of demographic associations on the Spanish versus English NIHTB-CB supports the need for distinct normative standards developed separately for each population. Fully adjusted scores presented here will aid in more accurately characterizing acquired brain dysfunction among U.S. Spanish-speakers.