Neuropsychological Assessment Battery (NAB): Introduction and Overview

1. Neuropsychological Assessment Battery (NAB):Introduction and Overview Travis White, PhD PAR, Inc.

2. Acknowledgment Development of the NAB was made possible and funded in part by the following grants from the National Institute of Mental Health: • 1 R43 MH58501-01 • 2 R44 MH58501-02

3. Introduction • The NAB is a comprehensive, modular battery of 33 new neuropsychological tests, each with an equivalent form, developed to examine a wide array of cognitive skills and functions in adults, age 18 and older. • Decisions pertaining to content and format were guided by results of a national survey of neuropsychological assessment needs and practices (Stern & White, 2000), and by guidance from members of the NAB Advisory Council and other consultants.

4. Rationale for the NAB • Arthur Benton (1992): The field of neuropsychology has lacked an integrated battery of instruments capable of providing highly sophisticated test data while requiring only a relatively brief administration time. • Oscar Parsons (1993): To meet current needs, such a battery should (a) have good psychometric characteristics, (b) include extensive normative and standardization data, (c) provide clinical information that satisfies a broad range of modern referral sources and questions, and (d) facilitate systematic research.

5. Goal of Development • The goal underlying the development of the NAB was to address these needs by producing a new and innovative neuropsychological test battery that provides a comprehensive evaluation of neuropsychological functions in less than 4 hours. • The NAB incorporates the conceptual framework of Bauer (1994) and Tarter and Edwards (1986) by offering a separate Screening Module to indicate the need to administer additional domain-specific Modules.

6. Attention Module Language Module Memory Module Spatial Module Executive Functions Module ScreeningModule Main Modules Screening Attention Domain Score Screening Language Domain Score Screening Memory Domain Score Screening Spatial Domain Score Screening Executive Functions Domain Score

7. Flexibility • For those areas of functioning not included in the NAB (e.g., motor functioning, effort, mood/personality), the examiner can expand upon the NAB assessment with his or her favored instruments. • The individual examiner may choose to forego the Screening Module and administer any or all of the five domain-specific modules to a patient, based on specific clinical needs. • In addition, the flexibility inherent in the NAB also allows for selection of individual tests from each Module – rather than administering an entire domain-specific Module – when this type of non-battery focused assessment is clinically warranted.

8. Survey • In order to ascertain the needs of the potential users of a new neuropsychological test battery, PAR conducted a comprehensive national Survey of Neuropsychological Assessment Needs (Stern & White, 2000). • The results served as a basis for the development of the NAB, vis-à-vis areas of functioning to include, length of battery, and other salient content and format characteristics of the battery.

9. Survey • An important finding was the discrepancy between • The amount of time respondents thought was ideally needed for a comprehensive neuropsychological evaluation given current instrumentation (Mode = 5 to 6 hours; 25 % stated 4 hours or less) and • The amount of time they thought was required to conduct a realistic and reimbursable neuropsychological evaluation in today’s health care climate (Mode = 3 to 4 hours; 49% stated 4 hours or less). • 89% of respondents stated that there was no commercially available instrument that provided a comprehensive evaluation within the current time/funding constraints.

10. Innovative Features of the NAB • Screening for both severely impaired and fully intact performance • Comprehensive coverage of functional domains • Combined strengths of flexible and fixed battery approaches to assessment • Avoidance of floor and ceiling effects • Reduced administration time • Coordinated norming (entire NAB normed on a single standardization group) • Demographically corrected norms based on age, education level, and sex • Provision of equivalent/alternate form • Increased user-friendliness for both examiner and examinee • Focus on ecological validity

11. Dual-Screening Capability • Screening capability rated as moderate-to-very important by 74% of the survey respondents. • In practice, neuropsychological screening is typically geared toward identifying patients who show no signs of brain dysfunction and no need for extensive follow-up testing. This approach has been formally incorporated into two popular assessment instruments, the Dementia Rating Scale-2 and Cognistat (NCSE).

12. Dual-Screening Capability • The NAB Screening Module provides screening recommendations at both ends of the ability spectrum. • For each NAB Screening Domain score, two recommendations are offered: (1) administer related module or (2) do not administer related module. Recommendations to forego the main module are made if: • the patient is fully intact (i.e., lacks impairment) and thus does not require administration of the analogous NAB Main Module because he/she would obtain similarly intact/above average scores • the patient is moderate-to-severely impaired and thus would not require administration of the analogous NAB Main Module because he/she would likely obtain similarly impaired scores • If the referral question requires greater quantification and description of the patient’s functioning, the user can always disregard the screening algorithm and administer the entire battery or the select functional Module(s).

13. Comprehensive Coverage of Functional Domains • Reviews of the neuropsychological literature (e.g., Lezak, 1995; Mapou & Spector, 1995; Spreen & Strauss, 1998) have identified seven major functional domains: • Language and verbal communication functions • Spatial/perceptual skills • Sensorimotor functions • Attention and related information processing tasks (including working memory) • Learning and memory • Executive functions and problem-solving abilities • Personality, emotional, and adaptive functions. • This conceptual framework has been confirmed with factor analytic studies of various neuropsychological batteries (Larrabee & Curtiss, 1992; Leonberger et al., 1992).

14. Comprehensive Coverage of Functional Domains • The NAB was developed with the overriding goal of providing a common set of core tests that serve as a reasonably comprehensive standard reference base suitable for most routine clinical applications. • Thus, the NAB is specifically not a “screening battery.” • The NAB is also not an exhaustive test battery that measures every conceivable neuropsychological skill and function.

15. Comprehensive Coverage of Functional Domains • The survey of neuropsychologists directly guided the final content composition of the NAB into the following six modules: Screening, Attention, Language, Memory, Spatial, and Executive Functions. • Within each of the functional domains, results of the survey guided inclusion and exclusion of specific subdomains of assessment.

16. Combined Strengths of Flexible and Fixed Battery Approaches to Assessment • The flexible and fixed battery approaches to neuropsychological assessment each have strengths and limitations. • In developing the NAB, we attempted to include as many strengths as possible, while avoiding as many weaknesses as possible.

17. Combined Strengths of Flexible and Fixed Battery Approaches to Assessment Therefore, the NAB has the following characteristics: • Constant background of tests • Focused, patient-centered examination • Shorter administration times afforded by the efficient screening/test selection • Minimal reliance on clinical decision-making in test selection. • Standardized administration and scoring procedures across all tests • Quantitative summary indexes along with numerous measures of qualitative aspects of performance

18. Avoidance of Floor and Ceiling Effects • Approximately 90% of survey respondents indicated that it would be moderately or very important for a new comprehensive test battery to be appropriate for high functioning examinees and should, therefore, avoid ceiling effects. • Approximately 73% of survey respondents indicated that a new battery should also be appropriate for severely impaired patients and should, therefore, avoid floor effects.

19. Avoidance of Floor and Ceiling Effects • Thus, a guiding principle in the development of the NAB was the avoidance of both ceiling and floor effects, when appropriate. • For most tests in the NAB, a continuum of difficulty levels was included so as to provide a relatively normal distribution in test performance. • Difficulty ratings were provided by the Advisory Council members and used in the initial creation and selection of individual test items. • In addition, item difficulty statistics were calculated on field testing and standardization data to assure the adequacy of distributions.

20. Reduced Administration Time • The NAB provides a reasonably comprehensive evaluation in a much briefer period than is currently available. • Approximately 71% of the survey respondents indicated that a realistic and reimbursable neuropsychological evaluation can be completed within 3-to-4 or 4-to-5 hours (excluding record review, interviewing, and report writing). • The entire NAB requires less than 4 hours to administer. In fact, in the Standardization sample, the majority of subjects completed the NAB in2.5 to 3 hours.

21. NAB Administration Time • Screening Module = 45 min. • Attention Module = 45 min. • Language Module = 35 min. • Memory Module = 45 min. • Spatial Module = 25 min. • Executive Functions Module = 30 min. • Full NAB (5 main modules) = 180 min. (3 hrs.) • Screening Module and Full NAB = 220 min. (3 hrs., 40 min.)

22. Coordinated Norming • Whereas much is known about the psychometric properties of individual neuropsychological tests (Franzen, 1989; Lezak, 1995; Mitrushina, Boone, & D’Elia, 1998; Spreen & Strauss, 1998), very little effort has been devoted to the examination of how individual instruments function within a battery (Russell, 1994). • Given the fact that 85% of the survey respondents reported using a customized battery, the lack of psychometric data on customized batteries represents a very large gap in the neuropsychological knowledge base, and may lead to critical limitations in the overall validity of clinical decisions based on neuropsychological test data (Faust et al., 1991).

23. Coordinated Norming • The NAB fills this critical gap by providing coordinated norms for all of the NAB tests and composite scores collected on the same standardization sample. • These coordinated norms allow for within- and between-patient score comparisons across the NAB. • Thus, the examiner can use a single set of normative tables (including the same age, education, and sex corrections) for the entire NAB, rather than dealing with the commonly used mixture of test-specific norms compiled in each examiner’s idiosyncratic “norms book.”

24. Coordinated Norming • An important consideration in interpreting the performance of individual examinees is the magnitude of difference between planned comparisons of scores. • The coordinated norming of the NAB allows users to interpret score differences with two types of comparisons: • Statistical significance of score differences • Base rate of score differences

25. Demographically Corrected Norms • The need to interpret neuropsychological tests within the context of an individual’s age, educational attainment, and sex has been well established in the field (c.f., Heaton, Grant, & Matthews, 1991). • Given that over 95% of the survey respondents viewed the availability of demographically corrected norms as moderately (18%) or very important (77%), the norms provided for the NAB represent a unique and critical feature.

26. Demographically Corrected Norms • The NAB demographically corrected norm sample consists of 1,448 individuals. • Separate normative tables are provided for all combinations of the following demographic variables: • Age (18-29, 30-39, 40-49, 50-59, 60-64, 65-69, 70-74, 75-79, 80-97) • Education (<=11 years, 12 years, 13-15 years, >=16 years) • Sex

27. Provision of Equivalent/Alternate Forms • An important aspect of neuropsychological assessment is the ability to monitor and document changes in functioning over time. • Survey results indicated that 96% of all respondents viewed the detection of change over time as a moderately (33%) or very important (63%) characteristic of a new comprehensive neuropsychological test battery. • Current neuropsychological instruments are poorly equipped to meet this goal because of a lack of equivalent, “repeatable” forms (Lezak, 1995) and a limited understanding of practice effects on neuropsychological testing (Sawrie et al., 1996).

28. Provision of Equivalent/Alternate Forms These needs were addressed in two ways during development of the NAB: • Two parallel, equivalent forms were developed for each NAB module during the initial development phases. • Because many repeat testing sessions occur 6 months or more after the initial evaluation, a test-retest reliability study of the NAB was conducted using a 6-month retest interval. Resulting SEMs and expected practice effects help differentiate meaningful score differences from artifactual practice effects.

29. Increased User-Friendliness The NAB is more user-friendly than existing instruments with respect to: • Modularity • Portability • Face validity

30. Modularity • Almost 90% of the survey respondents rated modularity as either moderately (29%) or very important (60%) for a new instrument. • Each of the six NAB modules are “self-contained” and may be administered independently of the other modules.

31. Portability • 76% of survey respondents rated portability as either moderately or very important. • NAB materials are highly portable because a minimal number of manipulatives are required and all necessary visual stimuli are integrated into a single stimulus booklet for each module. • All administration and scoring instructions are contained in the record forms, thus eliminating the need to juggle multiple forms and manuals during administration. • All materials necessary for an entire NAB administration fit into the provided attaché case.

32. Portability • Approximately 73% of the survey respondents rated computerized administration as only slightly important or not at all important. • Although this finding is initially surprising, it is understandable because even laptop computers significantly reduce portability and raise design and psychometric problems. • Thus, the NAB is administered entirely by an examiner (i.e., not by computer). However, there is a computerized scoring software package (NAB-SP).

33. Face Validity • Face validity is an important and often overlooked aspect of neuropsychological validation (Lezak, 1995; Nevo, 1985) • Face validity refers to whether a test appears to measure what it purports to measure, as perceived by: • Examinees who take it • Administrative personnel who decide upon its use • Other technically untrained observers, such as the examinee’s family (Anastasi & Urbina, 1997). • Tests that lack face validity are more prone to rejection by patients with brain dysfunction who are likely to be easily frustrated and fatigued.

34. Face Validity • The face validity of the NAB was rated by the members of the Advisory Council, and items and tasks with poor face validity ratings were eliminated or modified. • Although the attractiveness of test materials is not often discussed in literature on face validity, the NAB includes modern, inviting, and colorful stimuli, materials, and artwork, including high-quality digital photography.

35. Focus on Ecological Validity • Ecological validity is the functional and predictive relationship between (a) performance on a set of neuropsychological tests during a highly structured, office-based test session and (b) behavior in a variety of real-world settings, such as home, work, or school (Long, 1996). • Over 79% of Survey respondents rated ecological validity as being either moderately or highly important attributes of a new comprehensive neuropsychological test battery.

36. Focus on Ecological Validity • The development of the NAB specifically emphasized ecological validity. • For example, each NAB module (with the exception of Screening) includes one Daily Living test that is designed to be highly congruent with an analogous real-world behavior. • By definition, NAB Daily Living tests are multifactorial in nature.

37. NAB Materials • Manuals • NAB Administration, Scoring, and Interpretation Manual • NAB Psychometric and Technical Manual • NAB Demographically Corrected Norms Manual • NAB U.S. Census-Matched Norms Manual

38. NAB Materials • NAB Software Portfolio (NAB-SP) • Automates many steps involved in calculating raw scores and in obtaining normative scores and profiles. • Two score reports: Screening and Main Modules. • Choice of two normative samples. • Profile graphs, including overlays of multiple administrations. • Reports exportable to word processing programs. • Data exportable to spreadsheet and database programs.

39. NAB Materials • Test Administration Materials • Record Forms: • One for each Module • One per each of two NAB equivalent forms • All necessary instructions for administration and scoring

40. NAB Materials • Test Administration Materials • Response Booklets: • One each for Screening, Attention, Language, and Executive Functions Modules • One per each of two NAB equivalent forms • Used for tests that require the examinee to write, draw, or provide other similar responses

41. NAB Materials • Test Administration Materials • Stimulus Books: • One for each Module • One per each of two NAB equivalent forms • Contain all visual stimuli presented to examinee for all tests other than Map Reading

42. NAB Materials • Test Administration Materials • Manipulatives • Design Construction tests in both Screening and Spatial Modules use a set of five flat, blue plastic geometric shapes (Tans) based on the ancient Chinese puzzle game • Spatial Module Map

43. NAB Materials • Test Administration Materials • Scoring Templates • Numbers & Letters tests in both Screening and Attention Modules require scoring templates to score omissions and commissions.

44. General Principles Guiding the Development of the NAB • Tests must be easy to administer and score • Stimuli must be attractive and face valid • Total administration time for the five Main Modules must be 3 hours or less • Start with a large pool of items that represents a wide range of difficulty • Meaningful relationship between analogous Screening Module and Main Module tests • Theoretical foundation must combine empiricism (prediction) and cognitivism (constructs) • Test names should describe the content and/or procedures involved (“Dots” versus “Working Memory Test”) • Advisory council ratings must inform development activities

45. Item Development/Reduction/Selection • For each test, at least two times the final number of items/stimuli were initially created (sometimes 10 times), using detailed development criteria, objective ratings (e.g., word frequency), and computerized manipulations. • Results of Advisory Council Ratings AND numerous field testing studies guided both item reduction/selection and equating of forms.

46. Verbal encodability Clinical utility Difficulty Ecological validity Education bias Ethnic/racial/cultural bias Sex bias U.S. regional bias Linguistic demands Quality of stimuli, artwork Stimulus satisfaction Task appropriateness Overall task satisfaction Test/Item Characteristics Rated by Advisory Council

47. Standardization of the NAB

48. Standardization Sites • Collection of the NAB standardization data started in September of 2001 and concluded in October of 2002. • NAB standardization data were collected at five sites that were selected to provide representation in each of the four geographic regions of the U.S. • Four of the sites were located at academic institutions with known expertise in neuropsychology; the publisher’s offices in Florida served as the fifth site.

49. NAB Normative Samples The total NAB standardization sample consisted of 1,448 healthy, community dwelling participants, which formed the basis of the following normative samples: • Demographically corrected norms (N = 1,448) • Age-based, U.S. Census-matched norms (N = 950)

50. Age-based, U.S. Census-matched Norms • The Age-based, U.S. Census-matched sample (N = 950) was abstracted from the total standardization sample. • Closely matches the characteristics of the current U.S. population with respect to education, sex, race/ethnicity, and geographic region. • Purpose: For making inferences regarding the adequacy of the tested ability in more absolute terms, i.e., compared to the population as a whole.