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.

Identifying Health-Related Quality of Life Domains After Upper Extremity Transplantation.

OBJECTIVE: To identify the most important health-related quality of life (HRQOL) domains and patient-reported outcomes after upper extremity transplantation (UET) in individuals with upper extremity amputation. DESIGN: Verbatim audio-recordings of individual interviews and focus groups were analyzed using qualitative, grounded theory-based methods to identify important domains of HRQOL and provide guidance for outcomes measurement after UET. SETTING: Individual interviews were conducted by phone. Focus groups were conducted at 5 upper extremity vascularized composite allotransplantation (VCA) centers in the US and at an international conference of VCA experts. PARTICIPANTS: Individual phone interviews were conducted with 5 individuals with lived experience of UET. Thirteen focus groups were conducted with a total of 59 clinical professionals involved in UET. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Not applicable. RESULTS: Twenty-eight key HRQOL domains were identified, including physical functioning and medical complications, positive and negative emotional functioning, and social participation, relations, and independence. We identified key constructs for use in evaluation of the potentially substantial physical, medical, social, and emotional effects of UET. CONCLUSIONS: This study provides an overview of the most important issues affecting HRQOL after UET, including several topics that are unique to individuals with UET. This information will be used to establish systematic, comprehensive, and longitudinal measurement of post-UET HRQOL outcomes.

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.

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.

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.

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

Demographic factors impact neuropsychological test performances and accounting for them may help to better elucidate current brain functioning. The NIH Toolbox Cognition Battery (NIHTB-CB) is a novel neuropsychological tool, yet the original norms developed for the battery did not adequately account for important demographic/cultural factors known to impact test performances. We developed norms fully adjusting for all demographic variables within each language group (English and Spanish) separately. The current study describes the standards for individuals tested in English. Neurologically healthy adults (n=1038) and children (n=2917) who completed the NIH Toolbox norming project in English were included. We created uncorrected scores weighted to the 2010 Census demographics, and applied polynomial regression models to develop age-corrected and fully demographically adjusted (age, education, sex, race/ethnicity) scores for each NIHTB-CB test and composite (i.e., Fluid, Crystallized, and Total Composites). On uncorrected NIHTB-CB scores, age and education demonstrated significant, medium-to-large associations, while sex showed smaller, but statistically significant effects. In terms of race/ethnicity, a significant stair-step effect on uncorrected NIHTB-CB scores was observed (African American

Language measures of the NIH Toolbox Cognition Battery.

Language facilitates communication and efficient encoding of thought and experience. Because of its essential role in early childhood development, in educational achievement and in subsequent life adaptation, language was included as one of the subdomains in the NIH Toolbox for the Assessment of Neurological and Behavioral Function Cognition Battery (NIHTB-CB). There are many different components of language functioning, including syntactic processing (i.e., morphology and grammar) and lexical semantics. For purposes of the NIHTB-CB, two tests of language--a picture vocabulary test and a reading recognition test--were selected by consensus based on literature reviews, iterative expert input, and a desire to assess in English and Spanish. NIHTB-CB's picture vocabulary and reading recognition tests are administered using computer adaptive testing and scored using item response theory. Data are presented from the validation of the English versions in a sample of adults ages 20-85 years (Spanish results will be presented in a future publication). Both tests demonstrated high test-retest reliability and good construct validity compared to corresponding gold-standard measures. Scores on the NIH Toolbox measures were consistent with age-related expectations, namely, growth in language during early development, with relative stabilization into late adulthood.

Measuring episodic memory across the lifespan: NIH Toolbox Picture Sequence Memory Test.

Episodic memory is one of the most important cognitive domains that involves acquiring, storing and recalling new information. In this article, we describe a new measure developed for the NIH Toolbox, called the Picture Sequence Memory Test (PSMT) that is the first to examine episodic memory across the age range from 3 to 85. We describe the development of the measure and present validation data for ages 20 to 85. The PSMT involves presentation of sequences of pictured objects and activities in a fixed order on a computer screen and simultaneously verbally described, that the participant must remember and then reproduce over three learning trials. The results indicate good test-retest reliability and construct validity. Performance is strongly related to well-established "gold standard" measures of episodic memory and, as expected, much less well correlated with those of a measure of vocabulary. It shows clear decline with aging in parallel with a gold standard summary measure and relates to several other demographic factors and to self-reported general health status. The PSMT appears to be a reliable and valid test of episodic memory for adults, a finding similar to those found for the same measure with children.

Reliability and validity of composite scores from the NIH Toolbox Cognition Battery in adults.

This study describes psychometric properties of the NIH Toolbox Cognition Battery (NIHTB-CB) Composite Scores in an adult sample. The NIHTB-CB was designed for use in epidemiologic studies and clinical trials for ages 3 to 85. A total of 268 self-described healthy adults were recruited at four university-based sites, using stratified sampling guidelines to target demographic variability for age (20-85 years), gender, education, and ethnicity. The NIHTB-CB contains seven computer-based instruments assessing five cognitive sub-domains: Language, Executive Function, Episodic Memory, Processing Speed, and Working Memory. Participants completed the NIHTB-CB, corresponding gold standard validation measures selected to tap the same cognitive abilities, and sociodemographic questionnaires. Three Composite Scores were derived for both the NIHTB-CB and gold standard batteries: "Crystallized Cognition Composite," "Fluid Cognition Composite," and "Total Cognition Composite" scores. NIHTB Composite Scores showed acceptable internal consistency (Cronbach's alphas=0.84 Crystallized, 0.83 Fluid, 0.77 Total), excellent test-retest reliability (r: 0.86-0.92), strong convergent (r: 0.78-0.90) and discriminant (r: 0.19-0.39) validities versus gold standard composites, and expected age effects (r=0.18 crystallized, r=-0.68 fluid, r=-0.26 total). Significant relationships with self-reported prior school difficulties and current health status, employment, and presence of a disability provided evidence of external validity. The NIH Toolbox Cognition Battery Composite Scores have excellent reliability and validity, suggesting they can be used effectively in epidemiologic and clinical studies.

Factor structure, convergent validity, and discriminant validity of the NIH Toolbox Cognitive Health Battery (NIHTB-CHB) in adults.

The objective of this study is to evaluate the construct validity of the NIH Neurobehavioral Toolbox Cognitive Health Battery (NIHTB-CHB) in adults. Confirmatory factor analysis was used to evaluate the dimensional structure underlying the NIHTB-CHB and Gold Standard tests chosen to serve as concurrent validity criteria for the NIHTB-CHB. These results were used to evaluate the convergent and discriminant validity of the NIHTB-CHB in adults ranging from 20 to 85 years of age. Five dimensions were found to explain the correlations among NIHTB-CHB and Gold Standard tests: Vocabulary, Reading, Episodic Memory, Working Memory and Executive Function/Processing Speed. NIHTB-CHB measures and their Gold Standard analogues defined factors in a pattern that broadly supported the convergent and discriminant validity of the NIHTB-CHB tests. This 5-factor structure was found to be invariant across 20-60 year old (N=159) and 65-85 year old (N=109) age groups that were included in the current validity study. Second order Crystallized Abilities (Vocabulary and Reading) and Fluid Abilities (Episodic Memory, Working Memory, Executive/Speed) factors parsimoniously explained correlations among the five first order factors. These results suggest that the NIHTB-CHB will provide both fine-grained and broad characterization of cognition across the adult age span.

The cognition battery of the NIH toolbox for assessment of neurological and behavioral function: validation in an adult sample.

This study introduces a special series on validity studies of the Cognition Battery (CB) from the U.S. National Institutes of Health Toolbox for the Assessment of Neurological and Behavioral Function (NIHTB) (Gershon, Wagster et al., 2013) in an adult sample. This first study in the series describes the sample, each of the seven instruments in the NIHTB-CB briefly, and the general approach to data analysis. Data are provided on test-retest reliability and practice effects, and raw scores (mean, standard deviation, range) are presented for each instrument and the gold standard instruments used to measure construct validity. Accompanying papers provide details on each instrument, including information about instrument development, psychometric properties, age and education effects on performance, and convergent and discriminant construct validity. One study in the series is devoted to a factor analysis of the NIHTB-CB in adults and another describes the psychometric properties of three composite scores derived from the individual measures representing fluid and crystallized abilities and their combination. The NIHTB-CB is designed to provide a brief, comprehensive, common set of measures to allow comparisons among disparate studies and to improve scientific communication.

Development and validation of an episodic memory measure in the Mobile Toolbox (MTB): Arranging Pictures.

INTRODUCTION: Arranging Pictures is a new episodic memory test based on the NIH Toolbox (NIHTB) Picture Sequence Memory measure and optimized for self-administration on a personal smartphone within the Mobile Toolbox (MTB). We describe evidence from three distinct validation studies. METHOD: In Study 1, 92 participants self-administered Arranging Pictures on study-provided smartphones in the lab and were administered external measures of similar and dissimilar constructs by trained examiners to assess validity under controlled circumstances. In Study 2, 1,021 participants completed the external measures in the lab and self-administered Arranging Pictures remotely on their personal smartphones to assess validity in real-world contexts. In Study 3, 141 participants self-administered Arranging Pictures remotely twice with a two-week delay on personal iOS smartphones to assess test-retest reliability and practice effects. RESULTS: Internal consistency was good across samples (ρxx = .80 to .85, p < .001). Test-retest reliability was marginal (ICC = .49, p < .001) and there were significant practice effects after a two-week delay (ΔM = 3.21 (95% CI [2.56, 3.88]). As expected, correlations with convergent measures were significant and moderate to large in magnitude (ρ = .44 to .76, p < .001), while correlations with discriminant measures were small (ρ = .23 to .27, p < .05) or nonsignificant. Scores demonstrated significant negative correlations with age (ρ = -.32 to -.21, p < .001). Mean performance was slightly higher in the iOS compared to the Android group (MiOS = 18.80, NiOS = 635; MAndroid = 17.11, NAndroid = 386; t(757.73) = 4.17, p < .001), but device type did not significantly influence the psychometric properties of the measure. Indicators of potential cheating were mixed; average scores were significantly higher in the remote samples (F(2, 850) = 11.415, p < .001), but there were not significantly more perfect scores. CONCLUSION: The MTB Arranging Pictures measure demonstrated evidence of reliability and validity when self-administered on personal device. Future research should examine the potential for cheating in remote settings and the properties of the measure in clinical samples.

Development and Validation of a Vocabulary Measure in the Mobile Toolbox.

OBJECTIVE: We describe the development of a new computer adaptive vocabulary test, Mobile Toolbox (MTB) Word Meaning, and validity evidence from 3 studies. METHOD: Word Meaning was designed to be a multiple-choice synonym test optimized for self-administration on a personal smartphone. The items were first calibrated online in a sample of 7,525 participants to create the computer-adaptive test algorithm for the Word Meaning measure within the MTB app. In Study 1, 92 participants self-administered Word Meaning on study-provided smartphones in the lab and were administered external measures by trained examiners. In Study 2, 1,021 participants completed the external measures in the lab and Word Meaning was self-administered remotely on their personal smartphones. In Study 3, 141 participants self-administered Word Meaning remotely twice with a 2-week delay on personal iPhones. RESULTS: The final bank included 1363 items. Internal consistency was adequate to good across samples (ρxx = 0.78 to 0.81, p < .001). Test-retest reliability was good (ICC = 0.65, p < .001), and the mean theta score was not significantly different upon the second administration. Correlations were moderate to large with measures of similar constructs (ρ = 0.67-0.75, p < .001) and non-significant with measures of dissimilar constructs. Scores demonstrated small to moderate correlations with age (ρ = 0.35 to 0.45, p < .001) and education (ρ = 0.26, p < .001). CONCLUSION: The MTB Word Meaning measure demonstrated evidence of reliability and validity in three samples. Further validation studies in clinical samples are necessary.

Development of a vision-targeted health-related quality of life item measure.

PURPOSE: To develop a vision-targeted health-related quality of life (HRQOL) measure for the NIH Toolbox for the Assessment of Neurological and Behavioral Function. METHODS: We conducted a review of existing vision-targeted HRQOL surveys and identified color vision, low luminance vision, distance vision, general vision, near vision, ocular symptoms, psychosocial well-being, and role performance domains. Items in existing survey instruments were sorted into these domains. We selected non-redundant items and revised them to improve clarity and to limit the number of different response options. We conducted 10 cognitive interviews to evaluate the items. Finally, we revised the items and administered them to 819 individuals to calibrate the items and estimate the measure's reliability and validity. RESULTS: The field test provided support for the 53-item vision-targeted HRQOL measure encompassing 6 domains: color vision, distance vision, near vision, ocular symptoms, psychosocial well-being, and role performance. The domain scores had high levels of reliability (coefficient alphas ranged from 0.848 to 0.940). Validity was supported by high correlations between National Eye Institute Visual Function Questionnaire scales and the new-vision-targeted scales (highest values were 0.771 between psychosocial well-being and mental health, and 0.729 between role performance and role difficulties), and by lower mean scores in those groups self-reporting eye disease (F statistic with p < 0.01 for all comparisons except cataract with ocular symptoms, psychosocial well-being, and role performance scales). CONCLUSIONS: This vision-targeted HRQOL measure provides a basis for comprehensive assessment of the impact of eye diseases and treatments on daily functioning and well-being in adults.

III. NIH Toolbox Cognition Battery (CB): measuring episodic memory.

One of the most significant domains of cognition is episodic memory, which allows for rapid acquisition and long-term storage of new information. For purposes of the NIH Toolbox, we devised a new test of episodic memory. The nonverbal NIH Toolbox Picture Sequence Memory Test (TPSMT) requires participants to reproduce the order of an arbitrarily ordered sequence of pictures presented on a computer. To adjust for ability, sequence length varies from 6 to 15 pictures. Multiple trials are administered to increase reliability. Pediatric data from the validation study revealed the TPSMT to be sensitive to age-related changes. The task also has high test-retest reliability and promising construct validity. Steps to further increase the sensitivity of the instrument to individual and age-related variability are described.

VII. NIH Toolbox Cognition Battery (CB): factor structure for 3 to 15 year olds.

Confirmatory factor analysis was used the evaluate the dimensional structure underlying the NIH Toolbox Cognition Battery (CB) and the measures chosen to serve as concurrent validity criteria for the NIH Toolbox CB. These results were used to evaluate the convergent and discriminant validity of the CB in children ranging from 3 to 15 years of age. Results were evaluated separately for a 3- to 6-year-old group and a 8- to 15-year-old group because different validation measures were used in these age groups. Three distinct dimensions were found for the 3- to 6-year-old group: Vocabulary, Reading, and Fluid Abilities. Five dimensions were found for 8-15 year olds: Vocabulary, Reading, Episodic Memory, Working Memory, and Executive Function/Processing Speed. CB measures and their validation analogues consistently defined common factors in a pattern that broadly supported the convergent and discriminant validity of the CB, but results showed higher intercorrelation and less differentiation of cognitive dimensions in younger than in older children and in older children compared with adults. Age was strongly related to the cognitive dimensions underlying test performance in both groups of children and results are consistent with broader literature showing increasing differentiation of cognitive abilities associated with the rapid brain development that occurs from early childhood into adulthood.

IV. NIH Toolbox Cognition Battery (CB): measuring language (vocabulary comprehension and reading decoding).

Mastery of language skills is an important predictor of daily functioning and health. Vocabulary comprehension and reading decoding are relatively quick and easy to measure and correlate highly with overall cognitive functioning, as well as with success in school and work. New measures of vocabulary comprehension and reading decoding (in both English and Spanish) were developed for the NIH Toolbox Cognition Battery (CB). In the Toolbox Picture Vocabulary Test (TPVT), participants hear a spoken word while viewing four pictures, and then must choose the picture that best represents the word. This approach tests receptive vocabulary knowledge without the need to read or write, removing the literacy load for children who are developing literacy and for adults who struggle with reading and writing. In the Toolbox Oral Reading Recognition Test (TORRT), participants see a letter or word onscreen and must pronounce or identify it. The examiner determines whether it was pronounced correctly by comparing the response to the pronunciation guide on a separate computer screen. In this chapter, we discuss the importance of language during childhood and the relation of language and brain function. We also review the development of the TPVT and TORRT, including information about the item calibration process and results from a validation study. Finally, the strengths and weaknesses of the measures are discussed.

VIII. NIH Toolbox Cognition Battery (CB): composite scores of crystallized, fluid, and overall cognition.

The NIH Toolbox Cognition Battery (CB) includes 7 tests covering 6 cognitive abilities. This chapter describes the psychometric characteristics in children ages 3-15 years of a total summary score and composite scores reflecting two major types of cognition: "crystallized" (more dependent upon past learning experiences) and "fluid" (capacity for new learning and information processing in novel situations). Both types of cognition are considered important in everyday functioning, but are thought to be differently affected by brain health status throughout life, from early childhood through older adulthood. All three Toolbox composite scores showed excellent test-retest reliability, robust developmental effects across the childhood age range considered here, and strong correlations with established measures of similar abilities. Additional preliminary evidence of validity includes significant associations between all three Toolbox composite scores and maternal reports of children's health status and school performance.

I. NIH Toolbox Cognition Battery (CB): introduction and pediatric data.

This monograph presents the pediatric portion of the National Institutes of Health (NIH) Toolbox Cognition Battery (CB) of the NIH Toolbox for the Assessment of Neurological and Behavioral Function. The NIH Toolbox is an initiative of the Neuroscience Blueprint, a collaborative framework through which 16 NIH Institutes, Centers, and Offices jointly support neuroscience-related research, to accelerate discoveries and reduce the burden of nervous system disorders. The CB is one of four modules that measure cognitive, emotional, sensory, and motor health across the lifespan. The CB is unique in its continuity across childhood, adolescence, early adulthood, and old age, and in order to help create a common currency among disparate studies, it is also available at low cost to researchers for use in large-scale longitudinal and epidemiologic studies. This chapter describes the evolution of the CB; methods for selecting cognitive subdomains and instruments; the rationale for test design; and a validation study in children and adolescents, ages 3-15 years. Subsequent chapters feature detailed discussions of each test measure and its psychometric properties (Chapters 2-6), the factor structure of the test battery (Chapter 7), the effects of age and education on composite test scores (Chapter 8), and a final summary and discussion (Chapter 9). As the chapters in this monograph demonstrate, the CB has excellent psychometric properties, and the validation study provided evidence for the increasing differentiation of cognitive abilities with age.